Maybe we need three bathrooms, one women, one men and one other. Let them share the other bathroom with other perverts.
Enforcement of the rules will be enforced as far as common sense will allow. If someone is a known cross dresser or others know what sex they really are then they will be told that they have to use the proper bathroom. If they don’t comply then security can be called. That is all that we can do. That is generally what we do now. At least society on the whole will keep it’s standards.
We should lock up the mentally ill “transgenders” in institutions until they have rectified mind with reality.