I've never heard of a school requiring a deposit when booking an aeroplane - but if they did, I would go elsewhere.
The PIC should be able to cancel for any reason at any time without having to worry about getting money back, otherwise you'll have people deciding to go for it when they would rather stay on the ground just to 'save' that £50.
I'm sure no-shows are a pain in the arse, but the solution is surely to just bill people who don't bother to let you know that they've cancelled (or suggest that they b*gger off...)
As for "no patience for a new PPL question", don't worry about that Pinks
