@xiaomao
if your opponent gets enough unscouted mercies to kill you, you deserve to lose.
If you scout them and don't sacrifice a few inties to kill them, you deserve to lose.
If you can't do this and still walk your acu in a way that it can get snipe, you deserve to lose.
This should be obvious really. If you have a factory assisting another, and then cancel the assist. It should finish the current item in the cue.
The most annoying example is that if you cause a factory to stop assisting, it will even kill cues from its own build cue, including factory upgrades.
But you risk UEF players no longer being able to simply right click into the enemy base. What do you expect them to do, actually scout, preemptively destroy the kamikaze units, build some t1 maa? Madness.