Our gym has the 10 minutes late rule - if you're late to class by 10 minutes or more, you have to take a make-up and can't join the class. It's set for safety, but why can't the child just warm-up on the side to join in? Seems like it is too much more for convenience than caring for the kids - the little kids often are so upset at not being able to join their friends. Sometimes, there is traffic. Sometimes things come up. The big wow part of it is that sometimes it's backwards week, where the little kids rec classes start backwards - so warm-up is last - so, it makes you question even more, where's the sense in the rule?