I've heard stories about Gray Jays, aka "Camp Robber Birds" actually taking bits of donuts right out of people's hands in certain, un-named national parks featuring large volcanic mountains.
Of course I would never condone such an activity (cough, cough), but it was great fun to watch! Sort of a benign version of Alfred Hitchcock's The Birds. Uh, err, I mean, somebody told me it was fun... Yeah, that's what I meant.
All joking aside, it really isn't good practice to feed the animals. Last spring we had a fox run right up to the car at Mt Rainier National Park and put his paw on the side looking in the window. He was begging like a puppy, and it was extremely obvious he was used to mooching scraps. That's not good for the people or the animals. Even if he doesn't bite somebody when he feels threatened as some kid trys to grab the "doggie", what happens when the tourists leave for the winter? If he doesn't know how to forage for himself, then what will he do?