If you're defending with your queen, you're most likely going to lose. That's a horrible idea unless it's the only option. Thing is what if they call your bluff and trade down? You lose your queen.. unless they traded queen for queen or maybe 2 rooks for a queen you will surely lose. Also it's a bad idea because well now the queen is having to babysit a pawn for defense so your most powerful piece is tied down to defense and cannot attend to other tasks or to offense.. But I do see your point. If they attack O then maybe H will step in to shield him.