My DD(12) can have who ever she wants sleep here, but she has only slept out twice, and both times were at close friend`s of mine , who have daughters her same age.
And yes it shocks me that some of her friends (who I have never even met their moms) will just let them come home with me from school and hang out for hours. Call me crazy, but my kids are not going into someones home for a few hours to play if I dont know the parents well, let alone sleep out!
Even sleepover parties, I will let her go until midnite and then I will go pick her up and that is if I know the parents. You gotta do what makes you feel comfortable , they are your kids, keep them safe is what my rule is!