I can't think of a single pre-snap "procedural" foul that isn't rooted in advantage/disadvantage.
Let's see:
-False start. If a team A player is allowed to start early, he gets an advantage. If he just flinches, he can cause Team B to react and start early, and be offside.
-Illegal shift that converts to a false start. By the entire team not stopping for 1 full second before the snap, Team B may not be able to identify eligible receivers, and can't make positional adjustments. That is advantage to Team A.
-Illegal snap. Just like a false start, if the snapper is allowed to feint the snap, he can draw Team B offside, or, at the very least, cause them to 'catch' and reset themselves, and not be ready to move when the ball is truly snapped, which is clearly an advantage for Team A.
-Failure of a Team A sub to get inside the 9-yard marks before the snap. If this is allowed, a Team A sub can sneak onto the field unobserved, and run a pass pattern uncovered. That would seem to be a clear advantage for Team A.
-B interference with the snap. Self explanatory.
-B offside with contact. Self explanatory.
-B offside and behind the Team A line. Self explanatory.
-Team A breaking huddle with 12. Who are eligible? Who needs to cover whom? Clearly a disadvantage for B.
-Abrupt movements by Team B players within 1 yard of NZ. If allowed, Team B can cause Team A to false start, putting Team A at a clear disadvantage.
There are more, I'm sure. But, I think you can see the advantage-disadvantage element of these fouls.
The only possible way that a helmet coming off in, and of, itself can create an advantage/disadvantage would be if an opponent were to trip on the loose helmet, but there is nothing in the rules making that a foul. The basic helmet-off rule is solely intended to discourage loose helmets, all in the name of player safety. It has absolutely nothing to do with game play, or advantage/disadvantage. The 10SS component does address advantage gained by attempting to abuse the timing rules, if the clock is stopped to that team's advantage. In such cases, the opponent has done nothing to earn the benefit of the 10SS, and is not put at a competitive disadvantage by the helmet coming off.
In the given down example, the loss of the helmet was so 'incidental' that it wasn't even noticed by the officiating crew until well after the fact. Team B was not trying to get the clock stopped. Team A was not put at any competitive disadvantage. This incident was so obscure as to be totally inconsequential. Let the game play on. Yeah, have a discrete word with the player or his coach, maybe tell him to stay out for the next down, and to strap that helmet on, son.
Like I said before, if the few number of helmets coming off these days was the standard, we wouldn't even have this rule. Yeah, out in open, very noticeable, and a crew member stops the clock immediately, by all means, administer the rules as they are. I would just hate to have administration of this rule under such unobvious circumstances impact the opportunity for a team to win a game. Kinda like charging a Team A their final time out for the QB not having a mouthpiece during the last 15 seconds of the game, with 3/8, B-40, behind by 2 points.
I will now move on.