Do you flag it, or not
 

I am having a disagreement with a fellow official who works lower level games with us. IMO, if you see one out of four chin straps not fastened and you cannot tell the player before the snap, you do not flag it. You let the play go and tell him after the play. I woud flag a mouthpiece, but not one out of four chin straps. Mouthpiece is big safety issue and I think the helmet is still pretty secure with one strap not fastened. What is your opinion?

The only way I might possibly consider flagging this is if the player refused to keep it fastened. I have taken an official TO to send a player off so they could repair their helmet when they've claimed they couldn't buckle it.

I totally agree. Take the timeout, get it snapped, get it repaired/replaced if it will not stay snapped.

No flag unless he is observed unsnapping it during live ball action. If he refuses to snap it, no flag, but he cannot play.

I agree with MJT. Three out of four ain't bad. Definitely correct it after the play and send off for repairs if necessary. I have no problem with stopping the clock to fix equip. if the player brings it to my attention prior to the snap.