Who says you have to be a big dog to do the job? Don't laugh to hard. They are using some pretty small dogs for scent work these days. (money saved in the kibble department for sure)
I wish I had come up with this idea. Dog translation. I bet it makes the sign more visible. They should use this on the no pooping zone signs. And the clean up after your dog signs -"Make sure your human disposes of your waste appropriately."