If you have tweens and teens (over 12) who are in Circle C or Club O2 they only can sign themselves out. In fact, there really isn't even a sign-in/out process for those clubs. They just come and go as they please. But yes, I felt safe with reasonable precautions. He had to keep regular contact with us on the app, check in with us at certain times, and of course had ground rules like no going in someone else's cabin or letting anyone in ours or using pools, hot tubs, etc without us.