Whistle - what whistle?

Should Man U's goal against Lille on Tuesday have been allowed to stand? Lille obviously didn't think so, and indeed for a moment there seemed the possibility that they might have walked off the field in protest. Man U on the other hand, saw nothing wrong in what they had done - "quick thinking" was how they saw it. My view is that this highlights a problem created by the rules of the game being so vague as to allow more than one interpretation - and here we had a case of the two teams working to two different interpretations. Can a free kick be taken before the ref has blown his whistle? On the one hand, you have Law 5 which gives the referee power to stop the game to award a free kick (no mention anywhere in the Laws of a whistle, or how he is supposed to do this) but the Law is silent on how, and indeed whether, it is up to the referee to restart the game. Law 13, which deals with free kicks says "the ball is in play when it is kicked and moves" which at least suggests that it is for the side taking the free kick to decide when to take it. Most referees however require you to wait for a restart whistle, and here the confusion arises. Whatever the outcome of the inevitable investigation into what went on following the goal, I think consideration needs to be given to clarifying the rules, so everybody knows where they stand.