As a followup to Patrick's inquiry:
A substitution is taking place and the substitute is waved on by the referee well before the substituted player has left the field of play.
What actions are to be taken and does the team play down a man if:
A) The substitute commits violent conduct while the substituted player is still on the field
B) The substituted player commits violent conduct with the incoming substitute also being on the field.
The referee has clearly not followed the Laws of the Game and as a result he has put himself in a difficult position.
Now the referee has to decide if the substitution is complete. His tacit agreement by the 'wave on' suggests that it is complete so in
a) as the substitution is complete, the substitute is sent off and the team plays short
b) as the substitution is complete, the substituted player is dismissed and the team does not play short.
However if the referee is of the view that the substitution was not completed properly the answers are
a)The substitute is dismissed and the team does not play short with the player being allowed to stay on the field of play or substituted by another sub if one is available
b) The player is dismissed and the team plays short and the substitute asked to leave the field of play.
In these situation prevention is always better than the cure. That is why the referee should always follow the process as set out in Law 3 and then there is no debate about the matter
Thanks for the reply to my inquiry. That would have been my response.
While reminding referees that the formal procedure for substitution is expected to be followed, US soccer in its ATR advises that in cases of misconduct the substitute becomes a player when he enters the field after being beckoned on by the referee, i.e. the first part of your answer is the correct one in the United States.
The individual referee shouldn't decide how to deal with this problem. Either it's a completed substitution or not. The national associations need to give direction. Otherwise one referee make take deem the substitution complete and a second says it is not and two different consequences would occur.
The correct answer is the LotG one and that is the one that referees must follow. ATRs etc give advice to the referee. Simply put the substitute should not be allowed / beckoned to enter the field of play until the player has left. Then there is no need for interpretation. As the ATR states ""Deviations may lead to situations that the referee cannot settle within the Law.""
Beckoning on a substitute while the player to be substituted is still on the field of play is incorrect and poor procedure.
We know it happens and the ATR gives advice to deal with it. Elsewhere it is up to individual referees to make the 'best' decision after they have made an 'error' in not following the correct procedure.
The key is not to let it happen in the first place.