Ok, let's try this one:

Just before a snap someone cusses you out. During the play, it comes again and a third at the end of the play. You know it's the same person, but you don't know who because you were concentrating on-field.

Flag?

I have an advantage here. Officiating in German - but not being German, I can ask them to repeat themselves, because MAYBE I didn't understand correctly. So they have a chance to decide if it was an appropriate comment to make or not, and if they decide it was, then I can flag them for it.
If they are willing to repeat themselves...

I learned that sort of the hard way. I was U and I flagged a kid for the N word - I thought he was taunting an opponent. Turns out the DE was called Niggler and with the mouthpiece I couldn't here the l (I checked the player passes at half time too, and it was true)...

James

Yep, now I most likely have a flag. This isn't one isolated f-bomb, it's a sideline getting out of control. Plus, with the repeats, either I or someone else in the crew could narrow it down closer so we would probably know it at least that it came from a coach or a player and not from some non-team person.

No coach, its not baiting. Baiting would be him leading the coach in an effort to illicit a specific response just so that you can throw the Unsportsmanlike foul.

Asking a coach out of the blue "do you think I suck?" is baiting.

Asking a coach if they were talking to you after hearing "you suck" is not.

Jim is giving you an out in a situation where he really doesn't want to throw a flag giving your an opponent a free 15 yards.

Whether or not you want to take that out is another story...

REPLY: Had a game a few years back where the home team (underdog) blew a 13 point lead in the last two minutes of the game. Two fumbles which the favorite converted into TDs. As we ready for the kickoff after the second go-ahead TD, I'm standing on the sideline waiting for the ready-for-play. Behind me comes, "You refs succckkk." Flag flies and the frustrated coach demands to know from me who said it. I turn and say, "Number 41." Hearing that, number 41 says, "The helll it was! Jones said it."

"There's your answer coach."

Was R for a JV game last week. Several f-bombs by both sides from the outset of the game - none particularly loud and none aimed at the opponent, just too frequent and stated without reservation. Warned both teams separately in their huddles but still heard some muttering. Finally decided to advise both coaches the next one(s) would earn a flag. Went to the home coach and told him, "Coach I am hearing too many f-bombs out here. The next one will be penalized." His response (loudly enough so several along the sidelines could hear), "Okay, JUST TELL ME WHO THE F---ING A--H---S ARE AND I'LL GET THEM!"

I did a women's semi-pro game once. The coach kept calling his players mother-f's. I wanted to penalize him for improper use of a vulgarity.