Don't worry to much about that. If they were younger like 2 or 3, then you'd have to worry more because they would touch EVERYTHING. Not sure what their kids are like. Hopefully the parents are considerate enough to tell their kids off if they look like they're going to break something.

If they bring the kids, they will likely leave by 9:00 at the latest. Kids at that age get tired really fast at that time.