Just because the question is hanging there.
If fog of war is important, why make it possible to change sides so easily? It's not likely that the hundreds (or even tens) of people changing sides are supposed to forget the state of the side they left. While the info will go out of date, CVs move slowly so you only need to know the general area they are in.
I don't want to assume anything or put words in HiTech's mouth (ewwww!
) but that would seem to indicate a tacit approval of "spying", at least in so far as side switching is concerned. IMHO, its one of the things that makes the goal of winning the ground game appear less than compelling. If you don't like how its going for your present side, you switch to the side that is "winning" and take what you know to make it win faster.