A 4-10 @ A40. A12 drops back to pass. He scrambles around and runs to B's 40 where he throws a forward pass to ineligible A66 who catches the pass at B's 30 and rambles in for a TD. Ruling:

NCAA

As ball at A45 1st and 10

NFHS

Illegal forward pass at B40. The play will be penalized from there. 5 yard penalty and loss of down from the end of the run (B40). The Line to Gain has been reached so the Loss of Down is irrelevent. 1/10 for A from B45.

Sorry its from B45 not A45 as I wrote.

The coaches will not understand without an explanation, but there can not be OPI cuz it was an illegal forward pass. Therefor the only foul on the play is the ill forward pass. It is enforced from the spot of the pass (5 yards) and the LTG has been reached, so 1-10 for A at B's 45 yard line.

#66 is going to be upset but rules is rules...
 

NFHS rules:

If B accepts A's foul for an illegal forward pass: Enforce penalty from the spot of the foul, B's 40 yard line, 5 yards, to B's 45 yard line. The line to gain was the 50 yard line (it was 4th and 10 from A's 40 yard line), therefore A made the line to gain and is awarded a first down. The loss of down portion of the penalty does not apply when the A makes the line to gain after administration of the penalty.

Key points: Make sure the chains and down marker don't move, and get the correct spot of the illegal forward pass because this is the end of the run for penalty enforcement.

I know this is silly but lets say B declines A's foul for an illegal forward pass. The result of the play would be a touchdown for A.

Good point about no pass interference restrictions apply on an illegal forward pass. This applies to any illegal forward passes; intentional grounding, forward passes made by B or R after a change of possession, and forward passes by A made from beyond the neutral zone before a change of team possession during the down (hmm, perhaps some of you play gurus can come-up with some good ones based on those premises). Any other illegal forward passes I've missed?