I was at a game Friday night where the offense scored a TD which was confirmed by officials making signal and blowing whistle. As offense was lining up for conversion attempt, one of the refs noticed that offense had 12 men on the field during previous play and threw a flag for too many players on field. All the refs gathered together, waived off touchdown and assessed penalty. This call in no way affected outcome of game but I was just curious on this one. I figured since play was called a TD and whistled dead, the penalty would have to be called on the conversion attempt or ensuing kickoff. Thoughts??