Porta-potty is the entrance to a hidden rave

Stepping into a wardrobe was the way to get into Narnia. Stepping into the blue portable toilet (in a row of green ones) was the way get into a hidden rave at UK's Eastern Electrics Festival. Are they implying the DJ's shitty?

And, this isn't the first time this has been done. A music festival in Hungary did this last year: