We have spent a few vacations on concierge floors with our children and would never dream of letting them wander the halls without one of us. That is not only rude to the other guests, but unsafe for the child! Tell the concierge so he can knock on the parents door and get them out of bed to take care of THEIR children!
I can not stand people that let their children grow up like weeds and turn the other way when they misbehave. We all pay to go on vacation and expect a relaxing, fun time!