In a game I just finished which desynced in the first ten minutes, I was using the dev version (I mod frequently, so I just use it by default, though I had no mods enabled).  Anyways, after the other human in the FFA gave up, I decided to try something..

I decided to see what happens if I tried Ctrl+Shift+.+a+c+e on all enemy planets.  For those of you unfamiliar with the dev version of the game, that keystroke will colonize any selected planets.  In other words, if someone started to lose while using the dev version, they could just wipe out all enemies in this manner.  They'll receive a victory screen and it will count as a win on their record.  The other human had already quit, so unfortunately, I couldn't check if he would have received a loss screen.  My guess would have been no.

UPDATE: I just tested with another couple of players.  Once again, I received a victory screen and my ICO profile had it's win count incremented.  The other players however didn't receive loss screens.