Carroll asked me to test it and that's the result. http://www.littlegolem.net/jsp/game/game.jsp?gid=1569970
Unfortunately it seems working.
Obviously it's completely useless as soon as if I propose a hacked board to Carroll he still can decide if to accept or swap, so the balance of the game is preserved.
Polyomino Easter egg: if you add & move=ac|dc, you get a Tetris game where pieces start falling, but I could not find the keys to turn pieces, I am on Chrome!!! Anyone?