Exactly what happened to me.
Makes me think, while we were waiting at the music store for the signing session, I was at the beginning of the line, and I heard some guy next to me swearing. I turned aroung, it was a 10 years old kid, his pants were sinking. I said "Dude, are you really pissing your pants?" and he replied "Yes, I held that piss for too long..." And he just stood there, in his piss, and kept waiting for the band. At some point he did clean himself... with his hoodie, which he put back in his school bag. After a few minutes, a guy told him there were bathrooms inside, and the kid went inside to clean himself. He did come back in the line, with the same clothes, but kinda cleaned.
I took a picture of his legs standing in the piss on the floor with my cell phone, I just had to.