To the OP: Do you know if the gym is actually having to turn people away because of regulars sticking around for the second class?

I'm on a board of managers for one of our local YMCAs, and we've spent a fair amount of time debating on how best to handle class limitations. Some of our branches require you to sign in for a class twenty minutes before the class starts. Some just have a first come, first serve policy. Some allow you to sign in 24 hours in advance.

At least at our facility, we would discourage people from taking back-to-back classes if, in doing so, they denied somebody else an opportunity to attend a class. But if we added enough classes to meet the added demand, such that nobody was losing a spot because of doubling up, then I don't think it would be as big concern.