Some festivals try to work it so there's a family site or area which is supposed to be quieter, and a site where late night music is expected. I'm not sure how successful it is, but it seems a good idea in principle.

It can't be much fun with young kids or babies, if there's a party going on all night next door - and it's important that people can keep coming when they have young families, because thats where the future of the music lies. The great thing about folk music is that it is multi-generational, and once it loses that it's blown it.