Of all the years that I've been shooting out in the SoCal desert, I've only seen one and I still have the rattle.
Don't worry about it, with all the noise you'll be making they'll more then likely move away from you. If you're that worried about them then go out in the winter when they're hibernating. I see them as a non issue as long as you keep an eye out for them.
As far as gloom and doom about being bit, as long as you can get to an aid station/ranger station/ hospital soon you'll be fine. People that should worry are ones that are allergic to bee stings and stuff like that or have a comprised immune system.