Post scrimmage kick foul interpretation?

[WhoopWhoop!!]

I have a question.  What is the interpretation on the PSK rule as it applies to illegal substitution?  The other night there was a fourth and 3 situation in which the offense decided to punt.  The receiving team (punt return) had 12 men on the field.  The back judge waited until the ball was snapped (to allow the extra player to run off, which didn't happen) and immediately threw a flag but did not blow the play dead.  The punt was a touchback, and referees said it would be marked at the 10 yard line (10 yard penalty), change of possession, citing the new PSK rule.  Does it apply to illegal substitution?  If not, it should have been a first and 10 for the punt team, correct?  I'm completely confused.  If the rule is in fact the way as I have described it, what's to stop a receiving team from running 30 kids on to the field to block the punt or set up a return, knowing that it would only be a 10 yard penalty?  Thanks in advance for any insight.  

[blackmagic]

Ok... Just to tell you what happened to us. Other team was punting. 4th and 12. Kid ran on right before the snap. Making it inside the numbers before the snap. Making us have 12 on the field. Ref threw flag but didnt stop play. Let returner return ball. 

We were told. The down will be replayed with a 15 yard penalty. Which resulted in a first down. They called it illegal participation not illegal substitution.

Now in your situation. If 12 were on the field. I believe ref should have blown dead at snap and given defense a 5 yard penalty. Which would have resulted in a first down.

 

[badbird]

that is what should happen.  It is not a post kick foul.

[WhoopWhoop!!]

Ok thanks for your input. The refs were not budging saying it was a new rule. They kept saying it's the new PSK rule. It was a huge fiasco with the refs, but they stuck to their call. 

[Jambun82]

WhoopWhoop, that is a new rule change for 2017. The Back Judge was correct to not blow the play dead, as that is a live ball illegal substitution.

[s1nglewing]

From NFHS:

 

2-16-2h: Clarified that illegal participation fouls by the receiving team occurring during the kick are now enforced under post-scrimmage kick fouls.

Rationale: Illegal participation fouls by the receiving team occurring during the kick are now enforced under post-scrimmage kick fouls. Illegal substitution and illegal participation fouls by the receiving team occurring at the snap continue to be enforced from the previous spot.

[badbird]

which means they were wrong.  If you ran a 12th guy on the field after the kick it then they would have been correct