Your bus pass only costs something when it is used. Each time you swipe it, the bus company claims the money, so if you want to pay your bus fare, you are saving the country money.
How does a car park cost money to run? At the supermarket I can park for up to two hours free, so why does it cost something if I am there for three hours?
I don't know how BG gets away with the hospital parking as both hospitals that I have been to recently have barriers which won't operate...