This is one that could vary locally, so from the chilly north.....its complicated !!
When observing, I need to see that the referee knows and can demonstrate the required procedure at the level he is at, so, yes, stop game if needed, isolate/meet half way whatever is apt, name/number, reason and show card.
However if the referee has say, 7/8/9 cautions, as long as I can establish he can carry out the caution procedure, then that's all I need to see, so, without being set in stone, if 5 of them were done as per procedure and the rest flashed, I can live it.
Very similar to the subs procedure, we dont need the ref to go over 28 times in a game to do it, but, show me that you know the procedure.
If the game requires a slow card, say, then, give me it, slow it down and do it as taught. This is filed under good managment as much as carrying out procedure.
And flip side, flash me a quick red and everything is defused, I will give credit.
Neat, tidy, minimum fuss, clear to all what is going on, to who, and controlled
If post match I need to clarify who has been cautioned, then already either am gen just checking, or, the caution was not isolated for example and card was simply thrown into a crowd of players. Which is not a good sign.
I have prev requested a total change to the guidelines (here), as, soon as these guys progress, the "good?" practise they have learnt and spent a few seasons showing off, gets binned.