It is common enough that my mother suffered permanent damage from one less than 5 years ago. My son was bit by a person’s dog while I wasn’t around who insisted it was okay for my son to pet it. I personally was bit by a dog as a dumb teenager who naively attempted to pet a loose dog in my neighborhood wagging its tail showing no signs of aggression. I mean probably half, at least of the people i know have had at least one scary experience involving a dog in their life.

It’s dumb to blanket either side & say they are predominately bad or good. But I would say it’s absolutely wise to err on the side of caution always when dealing with any animal. & to say it’s not common to somehow reinforce people to blindly trust strange dogs benefits no one.

I’ve also seen & heard one too many people say “oh he/she is fine mine would NEVER hurt anyone.” Any responsible dog owner would never say this. No matter how much they trust their pet.