Back in 1980s, Yosemite National Park was having a serious problem with bears: They would wander into campgrounds and break into the garbage bins. This put both bears and people at risk. So the Park Service started installing armored garbage cans that were tricky to open—you had to swing a latch, align two bits of a handle, that sort of thing. But it turns out it's actually quite tricky to get the design of these cans just right. Make it too complex, and people can't get them open to put away their garbage in the first place. Said one park ranger, "There is considerable overlap between the intelligence of the smartest bears and the dumbest tourists."
People are lazy and impatient. Bears lack some intelligence, but they have all the time in the world. Make the garbage cans too hard to open, and people will get annoyed. Make it more accessible, and the smartest bears with nothing better to do will be able to get in too.