I have two laminated key shapes; one marked "Girls" and one marked "Boys". When one of my students needs to use a bathroom key, he/she does not have to ask permission. The student takes the key and then lays it on top of his/her desk. The other students and I can see at a glance if the key is avaliable and who is using it. My only rule is that students not leave the room when I am introducing a lesson or when we are in the middle of an activity-except in the case of an emergency. We talk about not abusing this bathroom priviledge, about proper hallway and bathroom behavior, and about responsibility and trust; about how trust is a gift someone gives to you and about how hard it is to get back once you lose it. It has worked well for my fifth graders. It is easy to tell if someone is abusing the system. Certain patterns develop and word of misbehavior in the bathroom has a way of getting quickly back to me. Usually a serious talk with the student or the temporary loss of his freedom of choice in using the bathroom is enough to get that student back with the program. I agree that sometimes a student just needs to move around a bit or needs a brief change of envioronment. A walk down the hall, even if it is just to get a drink of water helps to relieve tension and fatigue and helps students get focused again.