And that's the problem. They made a new rule knowing that there was literally no way to really determine the legitimacy if it was two different people, or 1 person playing on two nations. Sure, there are some signs it's likely the same person, as in one logging in right after the other....but even that could be a husband getting on, then letting their wife sit down and login to theirs. I can't honestly see anyway they can determine the difference besides purely speculation and one's assumption. As mentioned, sure there has been instances where a new alliance of new nations are made and you can easily spot that they were made to send aid/tech to a certain nation/nations and are blatantly obvious multis....but as I said, in most cases the person benefiting from that wasn't even punished. If not a ban, giving the benefit of the doubt the person receiving the aid didn't know, they should certainly have all the tech they earned removed from them.
I look at people posting ban appeals from the past months since the new rule was put into place, all claiming it was a family member that started to play, and by the new rule change, should be allowed. Most responses were either "you know it was the same person," or no response to their appeal at all. I for one would like to see all the multi's removed from the game, however the introduction of allowing more then 1 nation per IP has now left it up to the discretion of the admin staff to decide if it's true or not, which I can't see how they can possibly know without physically being at their house to see. Now, it's purely a risk game for the people who truly have two people in the same household wanting to play, as they could login too quickly from one another or something that might seem odd, and now they're both banned.
I was against the inactivity mode, mainly because I saw it as a way for people to dodge a war, but I at least saw the merit in it, plus I know many instances people had their nation deleted because something came up or wasn't able to log in, and then never came back because they didn't want to start all over. However, the rule change for nations on 1 IP i don't think was really that huge of a problem to begin with. I really don't think the amount of people not being able to play because someone else in the household already did was large enough to put into a place the headache that now as consumed the game, which is deciding if someone is a multi or not without physically being there to see. It merely opened up the game to be exploited easily, and no way to truly know besides a few obvious cases.
That's why either you go back to the old rule and make it simple, more then 1 nation on a IP = Banned, or you just don't do anything anymore to anyone besides blatantly obvious multi's, and realize you are letting anyone have as many nations as they please.