Nooka, should that happen then school won't be very empathetic, as your DS won't be legally entitled to work for many hours whilst in full time education They will argue, as will the LA, that he should work around his college course, not the other way round. Harsh, but those are the rules... as most reputable employers will know. Yet another rule 'for your own good' that is often so very counter productive when applied across the board.
For others insisting that the school cannot do this, I can only repeat, such stuff is my job, I know that, whilst it is highly unlikely and the school won't actively patrol looking for offenders, should a student be reported over and over again and show a 'fuck you' attitude when in tutorial, the school can follow their usual disciplinary route, which could lead to suspension and expulsion.
I have explained why. I am not guessing or hypothesising. As I said, this is my job. Dealing with students and parents who insist they are right and we are wrong is my job. Discussions such as this happen in my office on an almost daily basis.
It may seem archaic, nanny state and ridiculous but there are social and financial reasons behind all such draconian sounding decisions. Schools and colleges have a lot more they are expected to achieve that just keep kids in classrooms. Keeping the neighbours happy is just one of those things.
So if a school decides to 'ban' driving to school they can. It may be a daft idea, it may unpoliceable, but, as I said earlier, it may be part of a larger plan to remedy the situation, a hoop they have to jump through in order to come to a final, sensible solution. Frothing at the mouth won't solve it, sensible parking will!