I packed spray for my cook tent in remote hunts. Weight and bulk weren't concerns (I use a off-road rig to get out there), and the thought was that it might work on a young, curious bear, negating the need to kill it. The social jury here in Alaska is that it might work on such bears, but that, too, depends on the bear.
One friend has a bee hive on his deck (insanity where he lives up Eagle River valley). Sure enough, he got a bear on his deck, but instead of a thousand pound brown bear, it was a small black bear. He stepped out and shooed it away. In a few minutes it came back. He stepped out with the shotgun and fired a round into the air. It ran off, and in a few minutes it came back. He loaded a bean bag round in it and shot the bear on the fanny. It takes off............and in a half hour, is back. Finally, he puts it down with a slug. He calls the Troopers to report a DLP, and a Trooper shows up, throws it into the back of his pickup, and drives off. Didn't make my friend skin it out or even fill out the DLP report.
Would spray have worked better? Dunno. Maybe the bear would have been uncomfortable enough to learn something. Since it was a young, small bear, it might have educated him and saved his life for a decade or so. But, then, maybe not. But my friend had walls between him and the bear and daylight outside, which gave him plenty of safety to decide what to do. A bear in the night while you're wrapped up in a sleeping bag inside a tent? That's a whole different scenario. Like this guy:
http://www.bfro.net/GDB/show_report.asp?id=15821
Sorry. AFAIC, that guy wasted too much ammo (ie, >1 round) on warning shots. I'd have shot that sasquatch as sure as sin, then sat with my back against a rock wall until daylight and ready to shoot more of them. There is absolutely, positively no way I'm going out into the wilderness without at least two firearms: a rifle and a sidearm.