From what I've experienced/heard, Carnival does indeed do a poor job regulating the adults only sections without provokation. They won't really do anything unless you ask them, at which point they have no problem telling children to leave. Seems like it would make more sense to just police it to begin with, but oh well. If there are kids in these areas, just ask a staff member and they should tell them to leave.
And parents policing their own children? I'm pretty sure that's just an urban legend....
5/24/2008 - Carnival Inspiration
5/11/2007 - RC Sovereign of the Seas
5/14/2006 - Carnival Elation
