This question comes from myself:
Casey: At what point can a skip begin sweeping an opponents rock that is passing the T-Line?
Answer (according to the old guy who sits behind the desk at the club): You can only start sweeping when the rock crosses (touches) the T-Line.
This is interesting because I notice several teams that “warm” the ice behind the T-Line prior to the opponents rock getting to the Line. This, according to the rules guy, is illegal.
So there you have it. Good curling everybody. And don’t cheat!