If people think that the parking fee makes moral or logical sense, then that's the problem right there! (If you're worried about non-patrons using the parking spots, make them show a ticket to get into the lot. It's not rocket science. But then again, apparently rocket science isn't even rocket science these days, as a certain gentleman demonstrates...)Yall are looking at it wrong though. It's not necessarily a receiver fee, it's an access fee. Think of it as going to a sporting event, you already paid for your ticket to go inside and watch the event, but for every vehicle you bring there's a parking fee.
Even the notorious glutton that is Microsoft lets you download their OS for free. If you have a license it'll run, if you don't it won't (sort of.) They don't seem to be hurting for money.