Can't hurt. Yes I've heard of people using them. Mixed results, but that seems to be true for all bear deterrents, even guns. I carry bear bangers which go off like an m-80, but you can't buy them in the US. In real bear country (parts of Alaska) you'll find me with a bear bell, the bangers, bear spray, and a double barrel, and sometimes a buddy for backup. I solo a lot and there's no room for mistakes. I like to have options. Other than the double barrel it all fits in a pocket. I haven't had so many encounters since I try to avoid them, but usually you just need a noise to announce your presence. But there are places and times when a bear is not familiar with humans and being the top predator will come investigate noises. In my experience immature bears are even more dangerous than sows with cubs. Young and dumb.