There are some great comments on the thread--e.g., Saxon:
How long before the bears start lurking near the cans, waiting for a human to open one so the bear can "mug" the human and get at the contents (rather like an ATM mugger)? Based on my experiences with the black bears in New England, this would not be beyond a bear's reasoning capacity.and Mike Sherwood:
The party putting stuff into the trash is willing to spend about 10 seconds on the activity, whereas the party getting stuff out has no time limit. In order to cater to the lazy and stupid, someone has to do more work.
The configuration given doesn't work because it has the traditional open and closed configurations, while making the switch between those configurations needlessly complex. In this case, they need a recepticle that fails secure.
A mailbox like solution seems pretty obvious and rational to me. A cylinder with a horizontal axis has to be rotated to a position where it is accessable only from the outside in order to put trash in, then it rolls back to the position where the contents drop into a storage bin. A simple lock on the bin would keep everyone but the trash collector out of the bin, but allow everyone to deposit their trash in a designated location.
However, the trash can design could have been someone's thesis paper to prove that bears are pretty smart and a lot of humans are dumber than paste.