I recently just surrendered in this game: http://www.wargear.net/games/view/450271. For some reason it surrendered twice causing my scores to drop both times. 

The lesson here is to never surrender -

ps - Tom runs a re-index routine fairly regularly that goes through and cleans up mistakes like this.  It will get fixed.

I usually don't...there's been more than enough times where I've come back from an "obvious defeat" and won, but I had definitely lost this one and was just trying to save time and effort on behalf of my opponent. Glad to know that it will be fixed though =)

Yeah - I was kidding.  :)

I rarely surrender also but sometimes the odds are just too long to be worth the effort.

I would add that like in chess it is also a matter of courtesy to resign on dueling maps or when the game gets down to two players and defeat is immanent.