Superchief
TUG Member
I suppose it is hard for the GM to know. They don't want to violate their agreement with II. How does the GM know that the owner is going to show up later. After allowing the guest to checkin, they really have no way of enforcing the GC rule unless the evict the guest, something they don't really want to do. The GM is caught between a rock and a hard place.
An easy solution would be to take the credit card number of the owner by phone, and ask the owner to check in when they arrive. If they never check in, then they can be charged an additional fee. There are always possibilities of people gaming the system, but the whole class shouldn't be punished for a few misbehaving students.