As sheepluva pointed out, allowing this message to be legal allows naughtiness. The server usage of this message does not seem to use this check.
--- a/gameServer/EngineInteraction.hs Tue Oct 25 19:46:59 2011 +0200
+++ b/gameServer/EngineInteraction.hs Tue Oct 25 19:01:56 2011 -0400
@@ -28,7 +28,7 @@
check Nothing = (False, False)
check (Just ms) | B.length ms > 0 = let m = B.head ms in (m `Set.member` legalMessages, m == '+')
| otherwise = (False, False)
- legalMessages = Set.fromList $ "M#+LlRrUuDdZzAaSjJ,sFNpPwtghbc12345" ++ slotMessages
+ legalMessages = Set.fromList $ "M#+LlRrUuDdZzAaSjJ,sNpPwtghbc12345" ++ slotMessages
slotMessages = "\128\129\130\131\132\133\134\135\136\137\138"
gameInfo2Replay :: GameInfo -> B.ByteString