So, I suppose there is nothing against site rule about someone studying a map with a surrendered country and then joining the game with less than a minute left before the turn goes off and entering a bunch of moves at the last second. It is cheesy as heck, though. Myself and my ally adjusted our moves within a couple of minutes of the turn going off seeing that no player had joined as the surrendered power. I even refreshed with a minute left just to check to see if I needed to switch back. And yet between my refresh and the turn going off this guy joins the game and enters a full set of moves.
I don't suppose there is anything to prevent that, but a game should "lock" to a new player joining like 10 minutes before the turn goes off or something to prevent this kind of cheesy stunt. Quitters jack up games enough, but it seems almost like half the players who take over surrendered positions jack it up even worse.
Fortunately the guy who joined had his former ally attacking the zombie country as well, so all in all his cheesy stunt likely didn't buy him anything, but it still was a pretty cheesy move.