Is it not the case that the ref is the ONLY person to call a player back onto the pitch (not the linesman). You see players wait every week to get the signal from the ref to come back on. Sidibe walked back onto the pitch after play had re-started. The ref was right, not you.
Also, the ref can book a player for going off the pitch without his permission, I believe (correct me if I'm wrong on this one).
Correct, I've been sent off for going to change my boots on the touchline without permission.
FFS.