Here's a few questions that I would likely be able to answer fairly quickly if I had my rulebooks with me today:

A substitute enters the field during the down (assume that we only had 10 players on the field and the 11th enters the field after the snap). This is a live ball substitution infraction, correct?

What is the enforcement spot for this foul and what are the rule references?

For illegal participation (live ball), we use the All-But-One enforcement preocedure as usual, right? Is this the case with a live ball substitution penalty or is this treated as a non-player foul?

The plays that are in my head are:

Team A player steps out of bounds and returns. (Illegal Participation) ENFORCEMENT SPOT?

Team A (12th man) player runs off the field through his end zone (or wrong sideline) just after the snap. ENFORCEMENT SPOT?

Previous spot on both, I believe... although every time I answer what seems to be an easy one, screwy NF rules prove me wrong in 48 states (but not mine).

If the sub enters the field but does not participate, you have 5-yard non-player illegal substitution foul. Such a foul is enforced from the succeeding spot. If that sub then participates in the play, you also add on an illegal participation foul, which is enforced under the all-but-one principle.

Here is a play situation. A1 drops back to pass. Before he throws the ball, B11 steps on the the field and being to participate (illegal substitution foul for entering, then an IP foul for participating). A completes a 30 yard pass play. If A accepts the IP foul the 15 yards are enforced from the previous spot (as this is a loose ball play). Since the illegal substitution is a non-player foul, it is added on (5 yds.) from the succeeding spot.

One thing I'd like to ask.

Team A player steps out of bounds and returns. You bean bag the spot, then throw the flag if its a pass? Is this correct? Does it matter if the player doesn't touch the ball? Interception and makes the tackle? Ball thrown to other side of the field?

-Snake~eyes

Assuming there is no change of possession, no team A player can go out of bounds and return, unless he is blocked out. Our mechanic is to bag it when he steps out and to flag it when he comes back. It does not matter if it is a pass or run, it is a foul even if the run or pass goes to the other side of the field. He steps out and comes back, it's a foul.

If you have illegal participation from a player coming onto the field then the spot of the flag is the spot where the player came onto the field. Receiver voluntarily going OOB and coming back in, any player running on from sideline after the snap and participating, no difference. All-but-one using that spot.

Why do you bean bag the spot where he went out?

Because its not a penalty until he comes back inbounds.

What has that got to due with bean bagging the spot?

He when OOB. Big deal. There's no need to mark the spot.

It seems to me that bean bagging this spot is reinforcing to everyone that the player stepped out of bounds. Also, most of the time a player merely steps on the sideline while running (rather than running OB and returning down the field).

This spot gives us somewhere to throw the flag if it is a pass or if we decide he "participated" in the play if we do allow ourselves some judgement on those passes to the other side of the field.

Beats me. Honestly, I really don't know the purpose of the bag, but that is the mechanic we are told to use, so that is what I go with. Personally, I think it is overkill. What is the purpose of NCAA and NFL guys throwing hats when a receiver steps out? I would think they could remember it happening even if their hat(s) were still on their head(s).