Actually that's why I recommend another option.
Fill the gap with a bot, which would has a good properties, then we not forcing anybody, and also generate, or give a bot which is not so easy to kill, and balancing in a way.
Let's take your Scenario ([sG]Einstein): If some team member disconnect, because they feel losing that battle, then give team mates for those who wouldn't give up the hope, even if its absolutely impossible. Because those who would enjoy the game and try to do their best, tell the truth they won't be so happy after a time, when they lose 10/8 matches. :/ And the challenge would be still there, and won't became easier for those who belongs to the winning team.
The other that I could imagine, and that should be logical. If in a scenario there is a construction yard on the field, then allow to players, to rebuild their complete base, because the challenge will be increasing, and also the score numbers will lead, and for instance a new player joining, he/she won't feel that: "oh I joined at a wrong time".
(I can imagine both side, and I also know how hard to destroy a building if that is covered by good engineers )
The most important is for us, to solve this problem in a way, if not that way, then on this way, but it is very important, most of the times I joined to the looser team, and even when I tried my bests, after 8 lost matches I sad: I need to collect more energy to the next battle.
It is not just my aim, it's the developer's aim as well to make a good game, for each player.