Actually it didn't. "Zero tolerance" is a crutch for idiots.
The point was initially that somebody was trying to do something to combat threatening behavior. It very quickly deteriorated into, “I don’t want to be responsible for deciding whether a pocket knife is the same as a samurai sword, so we’ll just ban everything no matter what the item is or the reason is for it being there.” Now it’s a combination of power and cowardice on the part of administrators that gets kids like Matthew in trouble.
And you’ll notice the little quotey marks around “good idea” in my post.
Colonel, USAFR
Zero-tolerance was a response to the obvious futility of trying to win the War On Drugs.
The True Believers thought that re-doubling their fanaticism, and throwing all logic and reason out the window would curry favor with their Sky Gods of Prohibition.
Now we’re stuck with the cowardly idea, at least until Eagle Scouts start demonstrating the difference between a pocket knife and a real weapon to their oppressors, up close and personal.