Sorry to burst your bubble on it. I like the idea of the "going in for the kill" feature on defenseless craft, but with the fact that the dogfight windows are agnostic of each other makes it hard to check for escorts.
Can we get pointers to the other craft from the GeoscapeState somehow? We could then check for player craft that are targeting the transport, at the same location, and in a dogfight, to see if the transport is escorted.
Edit: Oh, we can check for other player craft from _game->getSavedGame(), right?