And if so, at what age would you leave them?
I've just endured enjoyed a week by the sea at a UK caravan site. On site was the usual camp club, where entertainment up until 10pm was aimed mainly at children...with the Reps singing and dancing their hearts out with the kids, so the parents could drink in peace relax 
Anyway, on 2 out of the 7 nights we were there, the compares who did the entertainment aimed more at adults/older families...called children up on stage as part of their act. When they asked the kids (who were totally unrelated) "Where are your grown ups?" the kids said they weren't with anyone as they'd gone back to their caravans.
The first child was about 7yrs old and the second about 9 or 10yrs old. Bearing in mind a lot of adults do tend to drink a lot of alcohol on holiday...and the club hires big burly security guards/bouncers from Thursday to Sunday (busiest period) I was a bit shocked that anyone would leave their child alone at night in a place like that 
So AIBU or do you think this is 'normal' and some parents see the Reps as baby sitters, despite the fact they're working and not there to be responsible for the kids?