We use a couple of windbreaks too, having 4 dogs, it is much easier to keep them in one place with the help of the breaks, and stop them being very inquisitive and upsetting other people by intruding in their awning or van, especially if food can be smelled by them!!!
Rather than a "Keep Out" message, ours are definately a "Stay IN" for the dogs.
Anyone is more than welcome to battle through a Mastiff, a Bullmastiff and two Lurchers to be "friendly",,just dont complain about the slobber on your legs, or being mugged for any food you may have in your hands.