I disagree. WEAR 9/11 inside job shirt and carry "I'm with Fred" sign.
OR
Carry "I heart abortion lobbyists" sign with a plain tshirt. Be sure you're behind him at all times so the news cameras catch you.
Edit: Disclaimer: I'm not actually advocating anyone do this. It's just something I'd like to see on tv. Problem is, it wouldnt' be aired. Nor do I watch tv.