This isn't a new thing. Garages have tried to rip me off several times over the years but because I have a reasonable amount of car knowledge and trusted friends to ask for advice, they've never managed it.
The worst were a place which tried to tell me my head gasket had blown (it hadn't) and one which failed to do any of the work I'd paid for. When I went back immediately, having obviously noticed that the car was still broken, I got loads of eye-rolling and 'if the lady isn't happy' etc. as they asked me to point out exactly what was wrong, clearly expecting me to be unable to.
In all honesty, I think all women should have basic car maintenance knowledge. Not only that, but get quotes for work beforehand and don't be afraid to challenge them on higher than expected bills.