Shared gate penalty fee

[POTKC]

But the airport doesn't lose money if an airline doesn't use any of its gates, because the gates are shared! Others use it and pay for it. Renting many shared gates is just like telling an airport "listen, I'm only flying to you twice daily, and I'll pay for those gates, but let's just agree that if I ever have more planes land they can all get gates, and of course I'll pay for those too." There's no reason for the airport to disapprove of that. They don't lose anything, in fact they're able to get more money from an airline in this case because every time a plane lands they get paid, and they never have to worry about that airline's planes getting stuck with no gates.

Why would the airport charge a fee for this? Seriously, putting in restrictions or fees for shared gates doesn't make sense.