The only public restrooms I've ever refused to use were the ones at my middle school. As you may imagine, letting a bunch of 11 to 13-year-olds (except that one 16-year-old girl in my 8th grade math class and I'm not making this shit up) freely use toilets without supervision is only a recipe for sorrow.
I walked into the bathrooms there once. Once. As soon as I smelled it, I walked right back out and never returned.
I never used my school's toilets either. Luckily I don't usually need to pee all that often. Which is handy if you ever find yourself in a situation where for 12-15 hours you're wearing a complicated medieval-esque costume that you have to take off in order to piss, but it's impossible to take it off by yourself and impossible put back on by yourself...which might be irrelevant because you might not even have a chance to take a piss anyway, expecially if it takes the better part of half an hour to put the damn costume back on.
This is why you make hose with a front opening.
It wasn't my costume, it was on a TV production so defacing the costume would have gotten me very, very fired lol. Plus it wouldn't have helped anyway because the outer layer of the costume was a shin-length leather armour...thing that was about as thick as brick wall (not literally, obviously) so I'd never have been able to cut through it, and it weighed several kilos and it didn't really bend easily. It was like carrying a dead cow on my shoulders. So I'd still have to had to taken that off and put it back on again which was a several person job because of how it did up.
I think there should be a law that costume designers are forced to wear their costumes for 15 hours before finalising the design lol.