Stephen Coleman gives an interesting look at the dangers of the proliferation of non-lethal (or more accurately "less-lethal") weaponry.
I've always felt that it was a good thing. I mean, it gives police an alternative to lethal force. The controversy always seemed kind of silly to me; sure it sucks getting pepper sprayed but at least you're not getting shot, right? Coleman presents some interesting figures about that. He tracks the rate of police-related shootings (including suspect suicides in police presence) among the Queensland police department, before and after they're given less-lethal weapons. The number of shootings remains largely unchanged, in the low single-digits per year. The number of pepper sprayings goes from 0 (obviously) to 2,226. So either they got that stuff just in time, or the police are applying their new, consequence-free toys quite liberally.
Then he mentions that situation in Moscow from a while back, where 118 hostages were killed by CS gas because police flooded the building with it indiscriminately and the hostages had no way to get away from it. Even worse, he notes that the police actually shot unconscious suspects in the head.