I'm sure there is a way around it. They already do find the way around for blue badge holders.
However, I think really hospitals like the income. And without it the public would still have to make up the shortfall via increased taxes anyway. So I'm not too fussed. Why should those who can/will walk or use public transport have to subsidize those who drive there? It's not ideal, but neither is telling the country income tax is going up by 1%, or the NHS is getting less funding and services will be cut.
Our hospital parking is getting ridiculous - it'll cost me £5 to get the bairn to her appointment this afternoon and she's got multiple appointments at the moment because of various issues she's got wrong with her. They touted the tram stopping at the hospital as the solution to all our problems with hospital parking but it's so bloody unreliable (car's got stuck on the tracks and blocked the service again which means we're going to have to car it in) that there's no alternative but to pay it (our part of town doesn't have a bus service at all now).
Don't think we have parking eye or anything running through - just an overworked bloke with a bag of parking tickets running around getting all the medical students who just leave their cars wherever they can get away with leaving them.