I got a target lock on Wedge while Biggs was away from him. Once they got within 1, I wanted to fire my proton torpedoes (from the Slave I) at Wedge. My friend pointed out that since Biggs was nearby, the attack had to go to him. Since I didn't have a lock on him, I couldn't perform that attack at all.
I agreed, were I to use a primary attack, or one not married to a target lock. But as the card says any attack that COULD target Biggs would automatically go to Biggs, this wouldn't apply. I said that it would be ridiculous to cancel out/negate any attacks because of Biggs being nearby.
My thought was that it applied to Biggs when you COULD target him, and since the proton torpedoes couldn't target him, they could still be fired on Wedge.