illegal participation on the defense
 

Fed rules:

The BJ missed his count before the snap. A had the ball 1st and 10 on the 50 yardline. The results of the play was a 30 yard run to the B 20 yardline. After the play, the BJ throws a flag for 12 men participating on defense. What is the enforcement?

Thanks in advance.

Half the distance to the goal, 1st down for A at the 10. Then you tell your BJ and LJ (with a smile of course) to get their S#$^ together and count while B is in the huddle.

This is the team's fault, not the Back Judges fault. And depending on the nature of the substitution, it might have been very late to get a count before.

And the biggest fallacy is that the defense actually huddles. Defenses often do not huddle and they have players running all over the place for substitutions. And if you use a common philosophy, you give the defense some time to get players on and off the field. And if you are doing the counting right, there should be someone else other than the BJ doing counting as well.

Peace

We debated whether the enforcement spot would be the previous spot because the "foul occured simultaneously with the snap".

Well these would be previous spot enforcements.

Peace

Correct, this is previous spot since the foul is simultaneous with the snap. If the player entered during the down and participated, you'd enforce via all but one.

I'm going with previous spot enforcement.
Choices: A could decline and take results of play and have 1/10 at B's 20 or accept penalty and have 1/10 from B's 35.

If BJ missed his count and didn't notice it until at the end of the play, how does he know if player entered during play or was there all along?