There is a general issue that could be discussed. Many things come to mind.
The win is obtained before the retreats phase. But a retreating unit can control a SC. In that case, a possible situation is that a retreating unit could not only obtain a SC for surviving, but also it could prevent the win!
On another hand, there is the case where your last unit is dislodged in the turn when someone wins, and that unit could be surrounded with no place to retreat. In that case, the unit would be effectively destroyed. Should that player deserve the "survive" status?
I don't remember what is stated in the official rules, but I have the impression that it would be "fair" (whatever that means) if a win can only be obtained at the end of the year, including the retreat and the build phase.

yes the win on retreat phase has been a problem and is not exactly correct.

to add another point to the discussion, you may want to check out this game:
http://vdiplomacy.com/board.php?gameID=134
Columbia lost the game in the very turn when Cuba won, and was counted as defeated because he had no more armies AND supply-centers

http://webdiplomacy.net/board.php?gameID=46206#gamePanel

(webdip)

I was high on painkillers, so I had some strange France play, but check out barn3tt getting in on a draw with no SC's.

because he had one unit still alive

btw why did you fraw that game? ;P

I took some painkillers for a bruised rib and lost focus. It was draw or CD.

ah, too bad!.. you had the victory at hand

I know, lol. The worst part is: I still don't have a victory as France on webdip.

Another issue with the end game on retreat phase is the dilemma if someone's retreats could have captured an SC off the winning player, does the game go to retreat phase or does it still give it to the winning player?

it still gives a win, which has been a problem and one that must not be easily fixed in the original code, otherwise it would be fixed by now.

It goes to the winning player, Norby, which is an issue.