The warnings from organisations such as the Scottish Hospitality Group and the Scottish Licensed Trade Association (SLTA) comes amid calls for stricter testing around the 6,000 capacity fan zone.
Nicola Sturgeon has repeatedly said the Scottish Government continues to keep arrangements for the fan zone under review, but claimed at a Covid-19 briefing on Friday there were “ethical issues” around making testing mandatory.
However, Glasgow MSP Paul Sweeney has called for a certification process, where each attendee must provide proof of a negative test taken no more than two days prior, before being admitted to the zone.
The European Championships, which get underway on Friday, will also come as much-needed relief for large bars and pubs in Glasgow which had experienced one of the longest and strictest lockdowns in the UK.
Stephen Montgomery, spokesperson for the Scottish Hospitality Group, questioned the logic of allowing the fan zone to go ahead amid rising cases of Covid-19.
He said: “While everyone is excited for Scotland to play in its first major tournament in decades, the Euros are going to provide a huge challenge for hospitality businesses in Glasgow. With Covid cases rising again, is the fan zone really something that should still go ahead?
"Obviously we want people to enjoy themselves, but they can do that in responsibly-run bars or restaurants with the proper health and safety protocols in place. Glasgow businesses simply cannot be forced back into level three because of something they did not ask for.”
He added: “For many hospitality businesses across Scotland, the next few months are going to be make or break, and while the Euros will encourage more people to pubs, bars and restaurants, with that comes its challenges.
"The hospitality industry is still facing the brunt of restrictions and we believe the current closing times in levels one and two are going to cause huge issues for staff, where they face a situation of having to kick customers out the premises before a match has ended.
“We need the Scottish Government to work with the hospitality industry so staff aren’t put at risk and operators can start to get back on their feet.”
Hospitality businesses in Glasgow which reopened fully yesterday following Glasgow’s move to level two, said the next six to eight weeks would be key to the survival of many pubs and bars.
Michael Woods, owner of Saint Luke’s bar in Glasgow, said: “We are delighted to get opened back up. Getting back open fully is key to us surviving.
“The sooner we get back to level one or level zero the better, but with the European Championships it is going to be vital for the business.
"We have room for 200 people watching games on the big screens, so it is fantastic and good timing.
"It has been horrendous. We have got a big outside space and it has helped us, but it is terrible for people without outside space.
"It has been hard and expensive to get back up and running. It’s not come without its costs with hiring new staff and that sort of thing, it is not just turning the key.
"We need to keep in level two for us to survive. Going back to level three or four would be the nail in the coffin for a lot of bars and venues. It’s key for us to get back to normal.”
Matt Colligan, the general manager at the Republic Bier Halle, said the reopening of their downstairs area with several widescreen televisions was a major boost to the bar.
He said: “We are booked out now for the three Scotland games and outside takes care of itself, it is great for us.
"The Euros are an extra advantage for us. It has been really really tough for everybody and we have been lucky because of our huge outside area, it is kind of like third venue.
"For a hell of a lot of bars that don’t have an outside, it [the relaxing of restrictions] is going to be vital for them.
"Every competition every two years is always massive for us. It is great that we have got this option and we are delighted and it will help our colleagues in the industry.
"Our area of Glasgow is getting bigger and bigger, so we want the traffic here because it makes the whole area vibrant and really busy.”
However, concerns around the potential behaviour of fans being kicked out of bars and pubs in the early evening before football games finish was also raised by the SLTA.
Colin Wilkinson, the SLTA’s managing director, said trade in Glasgow was “furious” about the fan zone and raised concerns about the behaviour of fans and drinkers.
He said: “Licensed trade businesses in Glasgow – and across Scotland – have faithfully followed the Scottish Government’s coronavirus guidelines and invested in all the necessary tools to stop the spread of the virus and operate in a safe and controlled environment. At one point they weren’t even allowed to play background music
“Now, we are told that it’s fine to have up to 6,000 people a day, each day for a month – 180,000 in total – gather in Glasgow when just a few weeks ago there were unruly, out-of-control crowds in George Square.
“Our question for the Scottish Government and Glasgow City Council is this – who will be controlling the Glasgow Green crowds? Can they guarantee that the strict physical distancing and other highly controlled Covid measures that we have been adhering to will be in place and controlled?
"Our big fear is that a fan zone could lead to further Covid outbreaks followed by a fresh lockdown, forcing licensed premises to close again when they have only just managed to start reopening again.”
Concerns about a potential outbreak from the event come after an expert on Friday urged a rethink on mandatory testing for the event in the hope of heading off any potential rise in cases originating in the fan zone.
Dr Christine Tait-Burkard, from Edinburgh University, said it was “positive” that fans would be outside, but that it was a “risk” not to test attendees.
One Glasgow MSP – Scottish Labour’s Mr Sweeney – said there was a need for a “robust testing protocol” to be in place for the fan zone, including a certification system to prove the existence of a negative test.
He said: “Given the fragile position in Glasgow at the moment with a recent spike in infections, I expect there to be a robust testing protocol in place, so that all fans attending the zone should present a certificate for a negative lateral flow or PCR test within the previous 48 hours before being permitted to enter.
"With same day testing available across Scotland, there is no excuse for not insisting on such safeguarding measures, even for those who have received a vaccination.
"The violent, riotous scenes of drunken disorder we saw in relation to the Scottish league trophy presentation day tend not to be a feature of international competitions, so I am hopeful that the event will be generally good natured and orderly.
"The fact that football fans will be permitted to attend Hampden for the Euro games should also hopefully minimise the level of frustration and subsequent disorder we saw in Glasgow last month and in March."
Some in Glasgow fear an alcohol-fuelled return to scenes of violence towards police officers and sectarian singing.
However, Calum Steele, general secretary of the Scottish Police Federation, told The Scotsman the expectation is for minor disruption rather than the scenes of violence witnessed in George Square just weeks earlier.
Thirty-two people have been arrested in the wake of an estimated 15,000 supporters gathering in the city centre square on May 15 after Rangers won their first Scottish Premiership championship in a decade.
Mr Steele said: “As someone who is a football fan and wants to see the team do well, I think it is beneficial for the drinking to be managed in as regulated a way as possible.
"The issue of disorder by the virtue of noise from drinkers, I think that is probably inevitable. But I think it is a world away from the rioting and violence and sectarianism that was seen in George Square.”
Mr Steele said the Tartan Army tended not to exhibit violence and could put domestic rivalries behind them when supporting the national team, with no great concerns around hooliganism.
Commenting, assistant chief constable Bernard Higgins, who has overall responsibility for Police Scotland’s operations around the Euros, said there was an “appropriate” policing plan in place.
He said: “Police Scotland has a truly enviable reputation for policing major sporting events and we are extremely experienced in policing events of this stature and importance.
“Our detailed process of planning with the event organiser and other partners to deliver a successful tournament has been ongoing for some time.
"As the public would expect, we have an appropriate and comprehensive policing plan in place to ensure everyone can enjoy the city and watch the matches while keeping disruption to the local community to a minimum."
Last week, a spokeswoman for Glasgow Life, which is hosting the fan zone, said: "It is not a requirement for ticket holders to show a negative result from a Covid-19 test to gain access to the fan zone or the stadium on match days.
“However, in the interest of public health, we would encourage all fans to take a test prior to attending, to help stop the spread of the virus as the country moves out of lockdown.
“Event plans will be continually assessed by partners against epidemiological conditions and Covid measures will continue to be monitored in the run-up to and throughout the tournament to ensure they remain appropriate.”
A Scottish Government spokesperson said: “The fan zone is ticketed and people’s contact details will be recorded to allow for any track and trace.
“We are encouraging everyone to take up the offer of twice weekly rapid lateral flow testing. This is especially important if attending activities where you are more likely to encounter more people than normal.
"Anyone who has a positive result or any Covid symptoms should not attend the event and should get a PCR test.
“Attendance at the fan zone provides an opportunity for people and families to gather safely in a controlled environment – with necessary physical distancing and hygiene measures in place – to enjoy the tournament.
“However, if there are concerns about the safe delivery of fan zone due to prevalence of the virus, then it may be necessary to review and modify these plans.”