Too many people worry about this stuff. The odds of a Brown Bear attacking someone is VERY high against it. The fact is, 99.9% of Bear attacks are caused from people surprising the Bear and not using simple common sense when in THEIR territory. Use a bit of common sense when walking in their territory and avoid walking through the thick stuff. Keep your eyes and nose open (yes you can easily smell a Bear) and make noise.
^^ This. First and foremost please remember what this poster said in his reply!
16n69, you seem awfully concerned about this issue. I'd highly recommend that you spend some time studying bear behavior in addition to planning for an attack. An ounce of prevention is surely worth more than a pound of cure when it comes to bears. I used to worry about these animals quite a bit, but these days I'm not nearly as concerned about them. I know more about bears now, I'm confident in my ability to travel in bear country, and if I do have an encounter with a bear I know of a number of things that I can consider doing before I'd have to shoot the animal in defense.
I spend virtually all of my free time in the mountains. I've been hiking, backpacking, hunting, camping, and shooting in bear country since I was a child. Here in Colorado we no longer have grizzly bears, though we do have a healthy population of black bears. Nevertheless, I've spent some time out in grizzly country, too.
The thing is, I think a lot of people get too obsessed with the idea that an attack is likely (when I was a kid I thought that way myself). It isn't. As such, while it may be possible to carry the biggest and baddest gun on the planet with you at all time, it usually isn't practical. There are certainly some places out there in the wilds where I'd feel a lot more comfortable with a long gun (or even a massive revolver), but those areas are few and far between in most of the United States. The Alaskans among us have the most exposure to those really heavily BIG bear-infested areas.
If I'm heading out for a backpacking trip where I might be intending to cover 25-50 miles with a fully loaded overnight pack, you can be darn sure that the weight of my gun becomes an important consideration.
Anyway, as for the issue of bluff charges vs real charges, I do agree with someone else in saying that an experienced and confident outdoorsy person can probably recognize the difference between the two in a lot of cases. In other cases the bear may push it beyond your imaginary line in the sand. There have certainly been numerous reports I've read in the past about bears bluff charging to within a couple of feet of the humans; I'm not waiting until the darn brute is licking me to make my move.
Regardless, like most "tactical" situations that are discussed here on THR, the issue of bear encounters should also be addressed first through avoidance, then through defensive tactics. How you carry yourself in the wilds, when and where you travel, and how you cook, eat, and make camp can all play a significant role in determining whether or not you'll have a bad bear encounter.
I once had a friend ask me what kind of gun I'd carry if I
knew I was going to be attacked by a bear. I told them it would probably be a howitzer. They laughed and gave me the "no, really?" question. Reality is, we'd all carry the biggest and baddest thing we could get our hands on if we
knew we were going to be attacked. But, we don't know if that will happen, and the odds are in our favor that it won't.
As for the video link you provided, that incident shows what I consider to be a true charge... not a bluff charge. That bear turned back only for the sake of self preservation, but that charge had every indication of a full-on defensive attack. The bear felt that her cubs were threatened and she went at that boat at full speed. Clearly the hunters on that boat didn't hesitate. The whole thing unfolded in probably less than two seconds in real time, and the guy drew his gun and fired it in that "oh poop" moment. Despite what the commentator said, I doubt his intention was to miss the bear. I imagine he missed the bear because he was trying to draw and fire in a moment when his adrenaline was hitting the ceiling as a giant enraged animal went toward him at full speed.