Broadstairs. (OK I admit it! It is my favourite festival) solved the problem by opening the school attached to the campsite up for 24 hours every festival day.
The classrooms and hall are in use by singers, storytellers, musicians and people just chilling out until at least dawn each day. Sleepers snore on undisturbed.
Over the years this has become the heart of the festival.
This is the thing that makes Broadstairs so much better than the other festivals, it has a soul.