LOL! That's the funniest thing I have seen in a long time!
How is the opponent leaving a match a problem? You get the win, both players save time and all is good. I don't see your argument. Sure you may not get to do some missions (eg. + pillz mission) but ELO really isn't the place for missions.
In tourney its annoying. Some players have no intentions of making points but just to stroll and slow down other players. They bring Uranus,graxs,Kolos,Ambre in tourney .
Now suppose you are fighting such player. You win first 3 rounds ,you have extra pills and in 4th round you can KO easily. But the player time outs or he concedes you will get 25 or 27 points only. If you played 4th round and win legally then you could have scored 35+ points. See,it makes a lot of difference in tourney. You could easily get 27 points for 2 round HKO but then you played 3 rounds and opp. left .
There should be some points improvements on time outs . Its very annoying because I have 7 timeouts wins in a single tourney and that has made a difference of over 100 points in my gameplay.