Re: 4 accounts per IP?
I've seen the rule mostly enforced on those who directly abuse the "beyond four accounts" rule through combat/player actions or patterns in house ownership. I have never seen someone with four accounts, who has a friend or two over once in a while, each of who play one character each, get banned under the rule. You cannot create more accounts, so you would need to walk them through the process of installing, patching, logging in, registering, and safely logging out before bringing them over (physically, to your house) to show them around the game.
By this point, you realize it's much easier to walk someone through everything over the phone. Find a good cordless phone with a headset jack. Mine came with headset jacks, and I picked up a cheap microphone/earbud combination on newegg for about ten USD. Granted, since I have IT experience, I know it's not possible to instruct *certain people* through complicated processes on a computer via phone, but I'm sure you'll give it your best effort
My friend and I used to play old DOS games at the same time when on the phone. It was cool because we were "playing together," just not in the same reality (parallel universe).