Left out of this discussion so far (I think) is mention of cooking.   I don't think it matters too much how well you have smell proofed your food storage, if you are base camping and cooking up bacon in the morning and fish in the evening.  Really strong odors like that are going to be a bear magnet for any bear downwind a mile or two.

An educated bear is going to know that there is good stuff in that camp, somewhere.

standard advise for camping in Grizzly country - cook dinner, clean up, then move on a mile or more and then make camp for the night.  Wonder why?

basically, except in the case of a problem bear like that one on Polly, its mostly a matter of luck that bears aren't all that numerous, and mostly, aren't in the same place at the same time we are, so any system will work for the most part.

Never had a bear in camp in Q, but have had issues with portage robbers a couple of times - those bears just know that there is food in one of those packs, in one of those canoes, and if they don't smellfood, they will keep looking anyway.