Here are two solutions I have had to come up with for hall passes to avoid students interrupting my class either for asking to use the bathroom or needing me to sign a form.
When I was but a wee teacher lad, early in years and fresh as linens from the dryer of college, I had a principal who was very strict about students in the hallway. Students must have a handwritten pass with their name, location, time, and teacher signature. At the beginning of the year (these were year-long classes at 50 minutes each), I gave them a sheet with ten passes on it. If they wanted to go into the hall for any reason, they would need to take one of those passes, fill it out, and have me sign it. The kicker? We had a teacher-made exam in the class and each pass counted as .5 points towards a bonus on the exam. I had just given them a total of 5 bonus points if they chose not to use the bathroom. Then, anytime a kid thought about going into the hall, they had to think about if it was worth giving up extra credit points. This worked for for a couple of years until I started teaching a class with a state test, and so could not give bonus points on the exam anymore. By that time, the hall requirements changed. Are there potential problems with this system? Yes, but I was young and didn't think about those at the time (and also, I never had any of those potential problems).
Brilliant? No. Extreme? No. Just two potential solutions if you are stuck with a hall policy that is causing interruptions in your class. How well will this paper hold up? Time will tell. So far so good, but we shall see. If nothing else, you may not have been aware of white board paper. So now you know and might have a cool idea of your own to use it with. If so, I would love to hear you idea in the comments.