I saw six bears this year in SNP during my SOBO hike. Two were small cubs with a sow, one yearling with a sow and one adult.
I added the 10 oz metal liner to mine and use it as a stool with my sit pad on top.It's my understanding that Yogi can puncture the Ursack otherwise and get his teeth into your food which would include bacteria.The bear supposedly cannot consume your edibles but can still ruin them.Bags made before 2014 are more susceptible to failure.Personally,I cannot tie mine tight enough to make it mouse proof but I don't stay in shelters and it has not yet been an issue.
During my 2011 thru-hike a bear thought she check out my backpack as I was resting on a road crossing. When I saw her an stood up she turned tail and disappear into the forest followed by two cubs. Yes they are there and they'll get your food if you leave it out, but they won't tangle with you for the food.
I saw 10 bears in four days this summer, they scared the crap out of me, they are so close and they don't move.
There will always and forever be a healthy populous of black bear in the park. I saw 3 thru the park. And only 1 charged at me. Guess that means I have been charged 33% of the time.
Trail Miles: 4,992.0
AT Map 1: Completed 13-21'
Sheltowee Trace: Completed 20-23'
Pinhoti Trail: Completed 23-24'
Foothills Trail: 47.9
GSMNP900: 134.7(16.8%)
AT Map 2: 279.4
BMT: 52.7
CDT: 85.4