My thoughts about penalty goals in extra are this. If the penalty was for a breach of the rules, ie, off-side, a penalty is given without the team being able to take a shot for goal. But what if the penalty given was for foul play..... or a professional foul. There would have to be compensation to the team fouled other than just kicking for field position. In these cases, a shot for goal would have to be given to win the game, or the offending player be automatically SinBin'ed for the rest of the extra time.
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While I am a fan of Golden Try, there must be an advantage to the team that is the victim of foul play.