It seems to me that once you've gotten in your car and driven to your destination, you're pretty much committed to parking there. How high do the prices need to be in order to keep you from parking at that point?
And how many pieces will the meter be smashed into as a result of the rage that these prices induce?
It's not as though people only become economic participants in the parking market when they arrive; they make the choice to participate when they choose to leave the house and when they choose to stay in the city for four hours rather than two.
Regarding the smashed meter problem, it should be a simple matter to add cameras to the devices.
Of course the problem is that you have to know where those places are. Hopefully they can put little signs on the meters that point people to cheaper parking.
I've actually done this before, on account of parking being too much of a pain or too expensive. It is, however, a "fool me once" scenario, since I'll now only go to the city for business, not pleasure (nor business-pleasure, like company holiday parties).