Lorna Taylor cranked up the volume of the Gerry Cinnamon song Hope over Fear "loud enough to wake a baby", a court was told.
Taylor, 53, shadowed the Tory team with her van "in an intimidating manner" round the former pit village of Cowie, Stirlingshire. She filmed the incident herself on a hand-held mobile phone -- because she thought the Tories were wrong to have been out on the stump after the Ariana Grande concert bombing.
Stirling Sheriff Court was told that Taylor had "reacted" to the sight of two Conservative canvassers, Gregor Ironside and Jeremy McDonald, on May 25th, 2017, because she thought campaigning was suspended in the wake of the Manchester atrocity.
In fact she was wrong, as local campaigning had formally resumed.
Miss Campbell said: "Loud music was blaring from the windows, which were open. The occupant of the address that Mr McDonald was at was annoyed by this, and said that the volume was such that it was disturbing a young baby that was in the house trying to sleep."
Mr McDonald therefore approached Taylor, and saw she was holding up her mobile phone, as if filming him. Miss Campbell said: "Mr McDonald asked her to turn the music down and she refused.
"Mr McDonald and Mr Ironside then began to walk along the street and the accused followed them in the van, driving very slowly and close to them.
"The manner of driving is described as being 'intimidating', such that the two gentlemen crossed the road as they were concerned about possibly being struck by the van.
"Throughout this the accused continued to use her mobile phone to film what she was doing."
Police traced her at her home on June 1st (2017) when she admitted being the driver.
Today Taylor, of Hilton, Cowie, who lives on benefits, pleaded guilty to threatening and abusive behaviour and using a hand-held mobile while driving.
Defence solicitor Stephen Maguire said the "very passionate" Nationalist had apologised to her former SNP MP Steven Paterson, who was unseated by the Tories at the election on June 8th (2017).
He said: "She was a member of the SNP. She is no longer a member, and as a consequence of what happened and the publicity it generated she was extremely shamefaced and embarrassed and apologised to her own party and her own MP, very much regretting the disrepute her behaviour brought."
He described the incident as "rather unfortunate".
He said: "Mrs Taylor's understanding was that the cessation of campaigning in the aftermath of the Manchester attack covered all campaigning until the Friday, but though national campaigning was suspended until lunchtime on the Friday, local campaigning had resumed on the Thursday.
"She hadn't appreciated that and thought that the canvassing that she saw was contradictory to the spirit of the respect that all parties showed to what had happened in Manchester.
"She was on her way back from the shops.
"If it had been on the Friday she would have driven on, driven away, but because it was Thursday night she thought it was something that required to be stood up to."
Mr Maguire said Taylor had "addressed her concerns" to "a senior member of the party" who was with the canvassers.
He said: "The reply she received was Ango-Saxon in nature, and very brief.
"She picked up her phone to record without thinking of the consequences."
Imposing the £500 fine, and ordering that six points should be endorsed on Taylor's licence, Sheriff Wyllie Robertson remarked: "If her motivation was to criticise people she thought were committing some offence against a period of mourning, it's a bit incongruous for her to be going around the streets blaring music out of her vehicle.
"It's a curious way of going about it."
Leaving court afterwards surrounded by half a dozen supporters, Taylor said: "I have said all I'm going to say about it."
Gerry Cinnamon's song Hope over Fear - which includes the lyrics "Tell Westminster Tories that Scotland's no longer your slave" - was penned for an independence rally in Glasgow's George Square ahead of the 2014 independence referendum.