I have found that dogs on tie outs are more likely to be barking non-stop and at the end of their tether than dogs who are actually on a proper leash. It's easier for the owner to ignore the barking when the dog is 15 feet away than when it's less than 6 feet away.
My dogs will bark if someone comes within their identified "home range". I will stop them. More than once, I have had a fellow camper tell me "they are bothering you more than they are bothering others". I still stop them - because it DOES annoy me.
They only bark if there is someone coming nearby. They don't bark while playing, or bark at shadows, etc.