I have changed my mind about this. Overstepping the time limit should lose
no matter what the positon on the board is (excepting the case where the
game has actally ended by checkmate, etc. but the player didn't stop his
clock).
The reasoning is simple--the opponent of the violator observed the time
limit. If he had also violated the limit, he might well have found better
moves. How much better, who can say? Certainly it is possible he could
have played enough better to change a loss into a win.