This is one subject I have always avoided because we just have a rule "no all nighters." When my children are invited to a slumber party or overnight at a friends I make it clear my kids can join the party and stay until everyone is falling asleep---BUT our bottoms sleep in our own beds...The only exceptions there ever were was Camp and there is was careful as to which camps they went to.
Even my teenagers had to be in their own beds everynight. The ONE and only time I broke my own rule was a little over two years ago when Tori spent the night with a girl friend and ended up dating and moving in with the girl friends older brother
I would rather drive across town at 2:00 am then even open the can of worms. It is not just the other families--it is the other families sons, neighbors, uncles....Some of these slumber parties have become co-ed! And often the parents put the children in a room and walk out and never even check on the children again...Some families have things in their homes like: drugs, guns, and porn.... I guess unless we make a list and ask we never know--and even then who is going to admit anything?
I was molested and raped by a cousin 3 years older then me--while spending the night with my other female cousin... In my Aunt and Uncles home....I was 12.