We don't have any hard or fast rules yet but we plan on having strict rules about dating. Right now my oldest is only 10. But obviously you have waited too long to discuss it if your child is dating someone and holding hands and hugging already etc.
I think a situation that is presumed benign, because it's just groups of kids having fun, is often not. My sil, the priest's kid, managed to lose her virginity at the age of 12 yo! I'm sure her parents were not letting her out on actual grown up dates. But it seems to me the church youth group was obviously very poorly supervised.