I have a planet fitness membership and both my kids are old enough to go by themselves as long as I sign off on it. My daughter just turned 18 so it doesn't matter for her anymore. I dropped my son off at planet fitness to work out and I got a call from planet fitness asking me to come get him. He accidentally started a fight between 3 adult men. My son was showering and I he didn't close his curtain all the way and two men were doing something with their phone. They weren't sure if they were just taking pictures or doing TikToks or something but they pointed the phone at his shower talking about the birth mark on his butt and making fun of him. My son doesn't know but this is what the other guy said his reason for punching them was. My son just heard them laughing. He didn't know it was about him. But guy C punched guy A and B and they all started fighting. They're all being banned and got arrested for fighting in the stalls. The lady said she understands it's not my son's fault but thinks maybe it would be best if someone was with him for now on. She didn't say he absolutely couldn't come alone. Just that she thinks it's best so no further altercations get started. I don't want to punish him because none of that's his fault but if he can't remember to close a curtain all the way maybe he isn't ready to go to the gym alone. I'm not sure. My daughter has been going alone since she was 15 and I never got any calls about her accidentally started a shower fight.

Edit: They deleted whatever was on their phone. At least that's what the lady told me and that they didn't know he was a minor even though my son looks young. And I don't think you should do that to anyone. Minor or not.