Law does not say that a coin is a non-negotiable part of a Referee’s equipment and many officials use discs of various descriptions to determine which way the winner decides to play. The FA statement quotes Law incorrectly and a ban like this is totally unreasonable. Players who get away with a yellow card when they deserved red don’t get retrospective punishment for far worse than such a minor issue as this.
Apart from teams wanting to stop Liverpool attacking the Kop in the second half or strong wind or low sun affecting things most captains just stay “as we are” anyway.