cute trick in simultaneous game

[LeTharg]

In a PBEM game, I had a more powerful fleet close to an opponents fleet. I pushed the attack button and, when asked which ship in his fleet to attack, chose the first one.

My opponent, guessing that I would select the first, ran for the hills with that ship and attacked a weak force of mine guarding a wormhole with the rest of his fleet. So my fleet ended up vainly chasing one ship while his main force snuck in behind me. Pretty cute. But it gave some ideas for some other sucker punches...maybe I can get back at him.

Anyway, does anyone have tactics to prevent this kind trick. I'm going to select my ship at random from now on but I suppose one could split ones fleet and attack each ship individually (too much like work).