I think we should debunk the egg cartons myth. This is probably based on the fact that the lining used in anechoic chambers is shaped similar to egg cartons. It is however made from a dense sound absorbent foam. Egg cartons may possibly provide acoustic dampening but have zero effect on noise transmission.
The main reason I enjoy festivals is that they bring together heaps of great people, many of them talented musicians, and I enjoy having a jam with loads of em. I am not so much fussed about sitting on a plastic chair facing a bank of speakers. Frankly I'd rather stay home and listen to the radio for free!
Is that weird or wot?
Keef