My Sister Did ItOnce my sister peed her pants in car.
We had been in a concert and were driving home. It was about 1 and half hour drive. My sister hadn't been to toilet for 5 hours but had drank quite a lo because it was hot summer evening. She didn't want to use toilets at concert place 'cos they're always so dirty.
After half an hour driving she told that she really had to pee. She was just told to hold it. After 15 minutes she was squirming and said "Mom I really gotta pee now, I can barely hold it". "That a big girl can hold it", mom told her. After few minutes I noticed that there was a small wet spot in her crotch. Soon I noticed she squirted little pee to her pants. "If we don't stop now I'll pee my pants", she said. "We can't stop for at least 15 minutes", father said. "Well then I'll pee my pants" she said. She relieved herself and pee began to flow into her gray shorts. "That big girl is peeing her pants?", mom said. "I couldn't have hold it for 15 minutes, and you didn't stop, just told to hold it", my sister answered. "Why didn't you go to toilet at concert?", mom asked. "They're always so dirty that I'd rather go in my pants", my sister answered. "It's okay to pee your pants if you want to, but don't go to car seat again" mom said.
Since then (and few times before as she has admitted) she has peed her pants on purpose because she hadn't wanted to go to public toilets/pee in public places.