The California Department of Fish and Game encourages people to take some precautions while in bear habitat. Bad news bears are bruins that have learned to associate people with food, and they'll go to amazing lengths to steal a meal. A wildlife biologist in Siskiyou County, for example, knows a bear that used to wait along a remote trail frequented by campers with pack mules. When a pack train came along, he would charge the mules to make them run. Then the bear would go down and have a feast.
Bears are intelligent, they have a keen sense of smell, and are very strong.
I received a report of a bear that broke into a Volkswagen van to get some food. For the rest of that summer, the bear only broke into Volkswagen vans. They either return to the original location, die in their new surroundings or become a problem in the new location. This is the quickest way to create a bad news bear. Besides, a bear that loses its fear of people may become increasingly aggressive toward them.