Looks like the new simcity game requires always online connection, the save files aren't even hosted locally they are hosted on EA's cloud.
http://www.destructoid.com/simcity-cranks-the-always-online-drm-up-to-eleven-240898.phtml
Which means if you disconnect for any amount of time the game will shut you out, plus it also means that you can only play the game until ea gets tired of paying for the servers, which will probably be sooner rather than later, I think they have shutdown the multi on games that were just a year old before.