Every festival I've ever been to or heard of is more or less the same: chilled out and safe. You should have no problem taking it in, just be cautious and put it in the bottom of your sleeping bag then roll it up, or something along those lines. Your shoe always works, but if it's a camping festival, why not put it in one of your bags? The shoe is reserved for a single show, but it has never failed me yet.

I've never been hassled at shows I've been to, be it a sold out crowd or one with 20 people. We smoke at all of them. ~