At the Nats game on July 4, i.e. yesterday:
Before the game, I hung out on the balcony overlooking the Will Call window. I'm pretty sure I saw Adam Eidinger heading for the gate, carrying a big posterboard-sized bag marked "art supplies". "Uh-oh; it's signage time," I said.
Sure enough, midway through the game, between innings, several people held up signs in the right field purple seats, spelling out: "STRIKE 4 DC STATEHOOD". Then they flipped the signs to read "BUSH PLAY BALL WITH DC".
Unfortunately, the signs were only revealed for a total of about 30 seconds. And, as is often the case with D.C. statehood campaigning, no-one noticed. Except me. (And I can't do anything about it.)
See, this is just weak sauce. Right field? During a commercial break? If you're going to pull off political signage at a ballgame, you have to go all out to get maximum exposure.
1. Scalp/sneak/bribe your way into the Diamond Club.
2. Situate yourself above the rotating advertisement just to the right of home plate.
3. Throw your sign up against the netting. The bigger the better.
4. Do it during an inning, so that the cameras will have no choice but to show your sign during a pitch.
5. Wait for the ushers to show up and ask you to remove the sign. When they arrive, refuse to take down the sign; argue instead, to stall for time.
6. It will take a couple minutes for enough security guards to come eject you from the stadium. But it will be too late; the entire MASN-viewing public will already know that Peter Angelos Eats Babies.
This would be most effective on a weekday night, towards the end of a game, when the Diamond Club has mostly cleared out and it's easier to manuever around the empty seats. For maximum TV exposure, do it on a night when ESPN or ESPN2 is showing the game, because it will be more likely to show up on their various highlight shows.
(Not that I've... um... thought this through to the last detail, or anything.)