Hey! Where did you get that picture of my dog?! :005:Wow they are similar.
Right, I probably won't be any help but I have very recently had the same thing.
Our dog (13 months) had thus far hardly ever barked. I mean, you could count on your fingers how many times. We just went on holiday for two weeks in a camper van. Also, the dog (cheers Inca) decided that that would be a great time to come into her first season
so she was very closely monitored. When out and about she was on a lead or if there was a decent space, a harness and long line. When at the camper, she was on a longish rope attached to the van. She started quite growlybarking her merry head off at passers by. (Never heard anything remotely growly either, before).
Exactly like you, I know she is super friendly with people of all shapes and sizes so did as you did and once she had stopped making a noise, let her off to go and say hello which she did in her usual waggly happy fashion.
I think she was feeling a bit trapped in a strange place and in the absence of knowing what else to do, she sounded an alarm just in case. I have heard that it is not a great idea to tie a dog out, as it can make them anxious and they only have fight or flight don't they? I tried after that to preempt the barking and let her off first so she could say hello without feeling trapped. That was fine. She was also barking at people walking past at night (understandable really) so we brought her into the back of the camper and blocked anywhere she could look through which sorted that one out. She thought that was great too, as she worked out how to get in our bed. At about 3am every morning. So that was great..I suppose if we were restricted so we couldn't get away and something unknown was heading for us, it wouldmake you feel more stressed than usual. Mine loves to go and say hi to everyone and everything and is always friendly but I guess normally she knows if she gets there and doesn't like it, she can get away again. We're home now and she's back to her quiet self.