I saw the documentary on TV a few weeks ago. The relationship between this guy and the bears was simply amazing to see.
A 400 pound female grizzly charged him, he just wacked her with a big stick and told her NO! The bear backed off.
I'm not sure I'd want to try it, but the bear knew him. I'm also sure he knows not to get too close to her cubs until she is ready for him too.
He was not harming anyone.