i vaguely remember being bit on the nose by a neighbor's dog when I was around 6 y.o. I think I was overpetting him and didn't of course know that his gutteral growl meant "enough" so he snapped and punctured my nose.
When Cody was growing, I was accidently bitten 2x, both times only because he was way faster than me at grabbing for his tennis balls. Both times I didn't take very good care, and developed blood poisoning and had finger splints and a sling.
Logan is very vocal and will warn when she's upset and will show her teeth, but has never bitten.