Eruv restriction (The sandwich board)

Question

Dear Rabbi, I've been following your Q&A messages with great interest. Recently my wife and I came upon a question and we bet eachother one hour of sleep (we have a small baby) that even though it was technically okay to carry with an eruv in place, that it would nonetheless be seen as against the spirit of Shabbat to carry a sandwhich board, even if the board were to read: "The Eruv is Up!" That is, say a person were interested in walking around the streets of a Jewish neighborhood wearing a huge sandwhich board over his/her shoulders proclaiming that it was okay to carry your talles, etc... because the eruv was up. What do you think? I know it's trivial because neither of us has the time or desire to make a big sandwich board proclaiming anything at all, but, well you know . ..