I agree it seems strange, but it is possible that is how things are done there. When my daughter was young, we had a house with a pool and it was large with plenty of rooms. We always had other kids staying over. There was food, the pool, and they were always welcome. I would say 75% of the parents never called me, met me or even cared where their girls were going. I would get the parents numbers from my daughter, call and introduce myself, letting them know it was fine if their child stayed over. Some didn't even return my calls. I think as long as that kid was out of their hair they were happy. I was divorced and single then, but the parents wouldn't have known if I was a crazy person, a RSO or the situation was bad. When my daughter wanted to stay over, I always called and introduced myself, then when I took my daughter over, I went inside to meet the parents and talk for a bit. Every parent doesn't do that.