Edit: David made a good point about black bears up north of the lower 48 being more dangerous. Perhaps those should be treated like Grizzlies? I'll qualify my comments as being about black bears south of Canada in the States.
I'll never buy into the triangle concept for black bears. I do see it recommended a lot. Grizzlies, I don't know much about. But it's well known that black bears have one of the strongest, if not THE strongest, sense of smell. So what's the point of doing the triangle thing? Here's my thoughts on it.
So I do the triangle. When I'm done heating water for dinner, I eat and place my freezer bag in my ziplock trash bag. This goes into an Opsack and into my mesh bear bag. I brush my teeth and brush and paste go into the Opsack. I hang my BB 100 yards from camp and head back. I do not have extra clothes so I don't BB the clothes I "cooked" in. And the pants I'm wearing has had snacks in ziplock bags in the pockets all day. I'm probably pretty stinky from hiking all day. I now have minty fresh breath from brushing. So of the 3 locations, camp is by FAR the location with the strongest odors. Which do you think a black bear would head to? And if it did go to the other sites, you don't think a bear could smell you 100 yards away from them? They are known to smell things miles away. I've seen people say that you should be upwind of the other sites. That's fine if the wind is only blowing one way but where I live and go, the wind shifts all the time.
My main concern with black bears is not being attacked, because that is extremely unlikely, but keeping them from getting my food. I do use an Opsack, although I'm not sure how effective they really are. But I hang my BB close enough to camp that I can hear any commotion so I can chase off a bear trying to get it. Which is negative reinforcement for the bear. If you BB away from camp and the bear does happen to get your food, they just got a positive reinforcement. Which is not good for anyone, especially the bear. This for black bears only. I certainly wouldn't try to chase off a grizzly.
I'm not trying to tell anyone what they should do. I just don't see the advantage, or the need, for the triangle system when in black bear country. Certainly not where I go. I don't see why it would be different for habituated bears. Although they'd probably just get to one of the triangle sites and start walking off 100 yards to find the camp. :)