S.S.
A few years ago my son had a problem with not taking time to go to the bathroom and ended up having accidents at school as well. My son just hated stopping whatever he was doing, especially recess, or missing out on what was happening and would end up having an accident. We ended up taking away his video game privileges each time he didn't try to make it to the bathroom in time. Once he knew there was a consequence he made sure he went and that ended the problem. Since your friends daughter is having the most trouble at school, I would make sure someone at school can remind her at the same times each day to the bathroom and actually going make sure she is going. I have heard of kids that go into the bathroom but won't actually go. I would still check with the doctor it could be a problem with her not having muscle control to hold it or an infection. Also, my niece wet the bed every night until she was 13 because she went into such a deep sleep she couldn't control it. There are many reasons this could be happening. I would definitely check with a doctor to rule out any medical reasons.