Neither of my BP's have ever bitten me, but I always make sure that when I go to handle them that I move slow and don't put my hand near their heads at first.
I also make sure to let them know I am there before I go lifting up their hides.

Sometimes they shy away but they've never actually balled up on me or even struck at me.

I guess you just have to make sure not to scare the snake. I mean, if you saw a massive hand coming quickly towards your face what would you do? Lol.

Hope this helps!