I have been on 3 Brown bear hunts and 5 Black bear hunts in Alaska..(all with the same guide) The first hunt, the first night, I asked the guide shouldn't we hang our food and cook away from camp? We always kept it clean, and when we broke camp you would never have known we were there..
I will never forget his response " we aren't that lucky to have a bear come into camp" I remember we camped on the side of a river for a couple days.. I woke up and went to take care of business in the morning.. There were fresh Brown Bear paw prints 30 yards from our tent.
On a moose hunt in Alaska, we had to climb up to 4,000 ft. we started the hike late that day and made camp at about 2,500. We camped just off the game trail, and I was instructed to piss 30 yds down from camp and he did the same thing up from camp. No bears showed up. Having skinned 3 brown bears in my life.. I can tell you their muscle structure is unbelievable.. One swipe from those paws and your done..
Bears have incredible noses, and I am quite sure that scentfree bags don't help much. They know your there.. If you run into the wrong bear ( just like people) there is sure to be trouble for one or both of you.. Once we were on the hunt, we took extreme care with wind direction and our scent.
For bear defense I would carry a 454 or bigger.. loaded with cast core bullets.. I know my guide was once out jogging in the mountains, and came over a small nob in the terrain.. A bear top another nob 100 yds downwind. He said that bear charged him immediately. He shot the Bear 3 times with his .44 and finally turned him on the 4th shot. Since that event he upgraded to a Tauras 454.
I have an tremendous respect for the bear.. and know would never underestimate them. 99% of bears want nothing to do with humans.. It is that 1% that scare the heck out of me..