Wait a minute gentlemen...you got it all wrong. Don't look at those in the school but rather the people they have to answer to: the community. There are all those parents that hound the district to the point where the administration puts the rules in place. Now I agree with this situation, however, if the schools don;t deal with absolutes, then they get sued.
In Michigan there is a school safety law which anyone caught with a weapon, such as a gun or knife is expelled (student) or fired (employee). That goes for a paint ball gun under the seat, or a key chain knife; even a knife as part of a nail clippers.
A couple years ago, a drama coach was carrying in a wooden rifle for a play. A parent saw them and called the police.
Needless to say, the public who complains are the problem.