Illegal Substitution or Participation

[mutzman]

After a change of posession, A runs onto the field with 12 players. There is no huddle and everyone lines up in a tight formation between the numbers. The extra player is lined up in a twins formation, one receiver on the line and one off. The snap in imminent, do I: A. Blow it dead at the snap, knowing there are 12 on the field and calling illegal substitution or B. Let the play happen with 12 and have illegal participation. The other factor in this is our state association has said that under no conditions should you let a play be run if you know there are 12 players on the field.

So... you make the call...