Why Ban Tasers?

Eugene Volokh, at The Volokh Conspiracy (why can't I come up with a cool blog name like that, I ask you?) notes that a number of jurisdictions have banned the personal possession of tasers, and asks if there is any good reason for it.

Now, the jurisdictions that he gives are the usual suspects (Hawaii, Massachusetts, Michigan, New Jersey, New York, Rhode Island, Wisconsin, plus Philadelphia, Baltimore, Chicago, and Washington, D.C.), so this is probably not an issue here in freedom loving Tennessee. I've sometimes thought about getting a taser to carry around campus (about once or twice a week when I get those emails warning about another robbery/mugging/assault that took place on the very route that I walk every day to get from the law school to the parking lot. But, of course, I shouldn't worry, campus is a super safe gun free zone!)