But where do you want to draw the line here? It is common practice for players to now cover their mouths with their hands during any conversation. Most of the time it’s about making sure that some ditzy lip reader doesn’t come along again and what’s said can be hyped up into a scandal. Think of Müller (Can this shit stop?).
But of course insults can also be said that only the addressee notices, as (perhaps) happened in the Prestianni case. So how should it be decided whether keeping one’s mouth shut is a punishable offense?
If the opponent says that he was insulted in this conversation?
That would open the door to false accusations. Given the way the football circus currently looks, it is not difficult to imagine that something like this would be used specifically to harm the opponent.
Therefore, I think that no practical solution will be found to penalize an opponent with red for simply speaking behind closed doors.
