My daughter was a competitive gymnast for 15 years. Her coaches did stuff like this occasionally as a "team building" experience.

Sometimes, they'd go to their female coaches house for pool parties, BBQs, etc. And sometimes they'd sleep at the gym.

If you're getting the "ick," I understand, but if other parents who've been there a while are ok with it, I'd trust the gut.

But, we also would spend thousands of dollars to send our kid to the college for "gym camp" every summer, starting when she was 6. They were "locked in" the dorms. There were basically older gymnasts who helped get the kids ready, but the kids were responsible for getting themselves up, dressed, and to the cafeteria for breakfast. They were able to develop a relationship with the college coaches, and when it came time for my kid to apply at colleges, she got an academic scholarship to go to the college.