In a perfect world, there would be a lot more single use ones. The bathroom is not supposed to be a social meeting place. Do what you need to do and vacate.
Even in the good schools, there are kids selling “inventory” (presumably because the kids have more money) in the bathrooms, too.
My son wants no part of that and it makes him uncomfortable to see it. If you tell, it’s your word versus them and you get jumped. He shares info with trusted counselors, they do a surprise locker search later in the day/week, and they keep him out of it.