On the ”bubble”...
Obviously your ref’s instructions come first.
We had a great AR classroom session looking at when you should flag. Far less often than I thought the simple answer.
If the ref is active one way or another, there’s no need to flag. Exceptions are if football expects and you flag the blatant breakaway, or insane foul right in front of you.
But there are lots of reasons not to flag fouls that are right in front of you... could the ref want to wait for advantage, and the other thing is better not to flag than foul after the whistle.
As an AR I have learnt, with good refs, there are lots of times when you don’t flag fouls close by. Maybe it’s close to the ref’s tolerance, maybe advantage, maybe not 100% sure.
But it feels awkward. A stare from a player, words from punters. I hate the feeling but I think we have to deal with it. I mitigate the reactions by quickly affirming the ref’s decision with a nod, or a ”good John” as I would on comms, and especially - to the player coming at me about to shout at me for not flagging - a nod, smile and ”clear foul, direct, come on...”
All that said: if you see a foul and the ref has not and there is no clear advantage on, wave that flag.
All the best refs I work with also say it’s fine to flag a pen - if they haven’t seen it - and you are 150% sure