Hmm, I am going to disagree on this one. I would not send my 5 yr old to spend the night out with a mixed group of boys/girls in that wide an age range. Especially, if I did not know all of the kids family situations/personally. Five year olds, in my opinion, do not have the maturity, cognitive ability to "know" if they are in a situation that is not good for them. Yes, there will be chaperones/coaches there, but, as with all large groups it is hard to know what is going on all the time. There was a situation at a gym in our area where they had a halloween lock-in last year. Some inappropriate things happened between the teenagers and some of the "young rec coaches" resulting in several coaches losing their jobs. I am sure this situation is rare, but with a child this young I do not think it is prudent to chance it. There are plenty of sleepovers/lock-ins to attend as they get older no need to push it.