Wow there are different scenarios, okay?
You two are constantly logging onto the same I.P. Address again and again and again. You're gonna get deleted. It's against the rules to use the same I.P. - tough luck. For all mods know, you are building up 2 nations and when the apocalypse comes you're going to aid yourself like there's no tomorrow. Don't like it; leave the game. Are you paying for this game?
In college, if you're in a dorm with a roommate playing CN, one of you will have to quit CN. The problem college kids are talking about is they're worried if past kids living in the dorms have logged in from the IP address. If you go to college you still have to ask a mod for an IP check.