I was talking to someone recently who used to be an elementary school principal. He believes that rules should be kept to a bare minimum and that they should always leave room for some flexibility. He told me that when he was young and just starting out he was appointed principal to an elementary school, and one of the first things he noticed about the building was that there were big signs in the corridors "No talking in the halls." He also noticed that the teachers and some of the children were constantly 'sh - sh- sh' to someone. And that the teachers were sometimes standing together whispering behind their hands.
So he considered:
1. The rule didn't make sense.
2. It was unenforceable.
3. Even the teachers found it hard to obey.
The solution - take down the signs. Occasionally remind people to be quiet in the hallways.