I'm thinking that there were two different bears involved. Twin Lakes is on the east side of the Divide, and a good distance from the pass. The 4 Pass route is on the west side, with a lot of wild country between it and the Divide.
Regarding RMNP, the Park instituted the canister rule a couple of years ago to try to ward off a potential Yosemite situation. The only bear issue at the time was a series of a few events where some bears figured out the Thunder Lake Trail, along which were 5-6 campsites. It was fairly easy pickings, if the campers were sloppy. The critters seemed to just move on down the trail until they got lucky. Funny, but I've never seen a black bear in my 35 years of hiking in Colorado. But after meeting my first grizzly (with 3 baby cubs) last month in GNP, up close and personal on a popular trail, I have realized how vulnerable I am to those guys. I'm thinking of taking bear spray now, wherever I hike, especially when I go alone.