I don't understand how much simpler I can put this. More than one player at one IP/location was a clear unfair ADVANTAGE with 0 balancing aspects, and was open to abuse. This new system still allows you to play together, but without all of the unfair advantages previously allowed. If you don't want to deal with the balancing negatives of it, then that is your decision. Oh yea, and it also prevents MASSIVE CHEATING ON MULTIPLE LEVELS.
I can't comprehend how the lot of you want to allow massive cheating just so a few couples get to keep an unfair ability to log each others account. And if you think that's not happening you are delusional.