In response to the cougar testing. The cougar testing was a test to determine if the cougar can smell what's inside of the bag. You can apply this to a backpacking scenario if you want, but given the percentage of cougar incidents, they are few and far between. I know people at animal sanctuary's and they have access to their enclosures and cages. Their knowledge of the animal, and how it reacts to certain foods was a basis for this test. What would happen if you put their favorite food within the bag, and then hid it within their cage. Would they find it? Well after hiding some of their favorite foods within the bag within their enclosure, NO they didn't detect the food.

Next, the food odor being released when you open a bag might not be significant enough to attract a bear. I would imagine the food odor drifting off before any animal could track it. If the bags are made strong, they should resist other little creatues from getting into them.