There have been some rather "passionate" threads on the forum on this issue. For me the question about carrying while backpacking is how and where so that I can access my weapon quickly when and if ever needed, but not have it interfere with how my pack rides or using poles. I have never taken it.

Car camping or driving cross county, maybe, but again, I never have.

Bear spray works great on bears and I bet it would cause the 2 legged variety lots of discomfort as well. I am not positive about this because of the concentrations; but pepper spray is pepper spray.