The two answers are indeed correct but it does raise a bit of anomaly. If a player is dismissed while actively involved in the game his team would have to play out the rest of the game with 12 men on the pitch and yet if a sub gets sent off then the team can still play on with 13 and use the remaining three interchange players

Coming onto the pitch to get involved is surely a more serious offence and yet it doesn’t leave the team as disadvantaged – perhaps the rules should be updated to state the offending team have to remove a player from the pitch?

I agree with you that it's a more serious offence, but I think the answer is to remove that player from the game without reducing the number of players on the field. Afterwards, ban the player for x games.

I think having a team play a man down can have too much of a negative impact on a match. If a player gets sent off early, it usually kills the game as a contest and spoils it for the people watching.

Slightly off topic, but I'd like to look at making a normal sending off less severe. With the player(s) sent off removed from the game entirely (as usual), perhaps teams that have lost a player from a first half send off could be allowed to go back up to 13 players at half time. If the sending off happened close to half time, that team could be made to play 10 minutes of continuous play with fewer players i.e. 40th-50th minute.

I guess the big question is should a player be punished for being sent off or the team

You say that a sending off has a negative impact on the game and kills the contest – well surely the point is for any team to be disciplined enough to stay with 13 men

The other way to look at it is from the perspective of the team fouled against – if I were a coach or player and one of the opposing team were sent off playing against me but the opposition were allowed to play on with 13 men then my team would gain no advantage despite being fouled against and yet the team they were playing next week would benefit through playing a weaker team due to suspension

A game of rugby should be a self enclosed entity – if a player commits a serious foul in the game, both he and his team should be disadvantaged through being sent off (it is after all a team sport). The ‘on report’ referee cop out is bringing this to an end of course

The sub will be looking at a lengthy ban

Correct - he will receive separate suspensions for striking and for illegally entering the field of play. The club will also pick up a hefty fine.