The CG, has no obligation to let me check in early. They have chores to do, and sites to cleanup. Or maybe just eat lunch in peace
Were they to let me check in early, I would be thankful, and if they wanted a small fee for such, I would understand that, and be happy to pay.
After all it is me that showed up early, not them. And if the shoe was on the other foot, and my site was not ready at the agreed to time, I would expect some compensation from them.
As I bet many of you would. Sword cuts both ways.