When I give my bear walk, I have an entire stop dedicated to going through all the ways we have tried to keep food away from bears that they have figured out anyway. The stop gets longer every year. Bears figure out our new “bearproof” things all the time.
As far as I know, BearVaults are still reliable bear canisters in Yosemite. However, that may not last for long, since we know Yosemite’s bears are smarter than those in New York!
The New York Times
Bear-Proof Can Is Pop-Top Picnic for a Crafty Thief
NORTH ELBA, N.Y. — It was built to be impenetrable, from its “super rugged transparent polycarbonate housing” to its intricate double-tabbed lid that would keep campers’ food in and bears’ paws out.
The BearVault 500 withstood the ravages of the test bears at the Folsom City Zoo in California. It has stymied mighty grizzlies weighing up to 1,000 pounds in the backcountry of Yellowstone National Park.
But in one corner of the Adirondacks, campers started to notice that the BearVault, a popular canister designed to keep food and other necessities safe, was being compromised. First through circumstantial evidence, then from witness reports, it became clear that in most cases, the conqueror was a relatively tiny, extremely shy middle-aged black bear named Yellow-Yellow.
Tales from Yosemite - Jeffrey Trust's Blog 
July 27, 2009 at 5:51 pm
I winced this morning when I heard a fellow permit-seeker say she had a “Bee-Vee 500” for her trip to Mt. Whitney on the JMT because of this article. I bit my tongue and said nothing. I’m waiting for it to be taken off the approved list, though.
Edie
We really should meet up for coffee sometime, Jeffrey!