Residents Parking Permits - fair point, though in Exeter it's 10p per day.
Re hospital car parks, I agree with differential charging to the extent that the incentive should still be to nudge people into not driving where feasible, and to leave what spaces there are to those in genuine need. After all, car parks do bear a cost to someone, and I don't think it unreasonable that the NHS should recoup part of that cost from those using theirs.
From my experience of habitual car drivers – those who can't imagine ever going anywhere without driving there, even if it's just round the corner – they will come up with every excuse under the sun why they can't possibly be expected not to drive right to their destination and park there. But presented with a fait accompli, all of a sudden they find a way (whilst carrying on moaning, of course).