Yes, photos of signs can be funny and clever, and I’ve seen great ones. But a person holding a sign, lacking any expression, gives me no essence of that person, and the sign takes on too great an importance. I always think of it as cheating in photography.
I’m not saying a sign can’t be part of an image, but if you are relying solely on the sign to tell a story, you’re not doing your job. maryvignoles.com