I think bear spray, even though I carry it, is as much a false sense of security as carrying most weapons by most people (like almost any pistol) when it comes to actually being deployable in most the scenarios with bears that actually result in maulings. They seem to almost always be sudden attacks where even a skilled person would not be able to deploy their weapon or spray in time. Most times when people could have enough calmness to use the spray effectively it would be in a situation where just shouting would probably do the same thing. Of course if your friend is being mauled it might get the bear off.