Frequent requests to go to the bathroom may be an indication that children have a medical problem, either chronic or temporary.

Teachers didn't understand this years ago, and still seem to be unwilling to acknowledge it. Maybe giving them a strong dose of laxatives and locking them in the classroom overnight, without access to a bathroom, would teach them a lesson.

If it's an ongoing problem at home, the parents should have the condition diagnosed and inform the school about it.