This is an old topic I guess:
Just played a game (Gap of Rohan) where UEF T3 Transports where used rather ingenius for controlling airspace (killing T3 bombers, ASF) and when they reached critical number they where also used as an invincible ghetto deathblob.
Quite a long game with some dead / leaving players so I'm not sure if it desyncs.
All I can say... It's not the intended use and I don't really know how to counter that? Do their AA have splash ?