When I was a kid I don't remember too many sleep-overs at my mom or dads apartments. I had one friend who was also an only child and sometimes we would have a sleep-over at his apartment. It was very cool because his mom would go to bed and we would stay up all night talking and watching T.V. Then we would sleep until 12 noon. Since both of my parents apartments were pretty small friends would stay late sometimes but their mom or dad would usually come to pick them up. So I guess for me late-overs have been around for a while.
Today "late-overs" are just like sleepovers minus the sleeping part. Kids still wear their pajamas and bring their sleeping bags to watch movies in. They do crafts, play games and gossip. Then before 10PM mom and dad come to pick them up.
What today's parents like about this is their kids are home in bed their own bed at their regular bed time. No one gets a call at 2 in the morning to pick up their homesick child with a stomach ache. Plus, mom and Dad get to sleep in too.
My daughter Kim loved to have sleepovers at my house and her friends houses. I never liked them but realized it was a part of growing up. These days taking responsibility for another family's kid is a very big deal. It seems like parents were much more laid back when I was growing up. One time one of Kim's and one of her friends actually removed the screen to Kim's bedroom window and climbed out in the middle of the night. They were hoping to meet one of their boyfriends. The only way I found out about this was the screen left on my lawn. The girls couldn't figure out how to put it back in. Yup, I totally endorse late-overs instead of sleepovers!