Several years ago or then probably 16 or 17-year-old snuck out of his room after he was back for curfew. He and some friends were hanging out on the stairs talking, and security came, got their room numbers, sent them back home, and we got a letter the next morning telling us what happened and to make sure our kids stay in after 1 AM.
I think it really varies by ship. Other times I know our kids have been out getting pizza at Sorrento‘s and no one ever said anything.
Before anyone slams me for being a bad parent, we all agreed that they would be in by 1 AM, and I only found out about these things after the fact. I don’t share a room with my teen kids and I don’t check on them multiple times after 1 AM.