So since I'm married I can have "my wife play" strategus? What a great deal, getting another copy of Warband tonight.
Why not just make a rule, one CD key per MAC address. No exceptions...
If you only have one computer, you shouldn't need more than one Warband account on it. Make your friend, brother, SO play on your account. There's no down side to this (aside from they can't play in strategus on an alt, but they can't play when you're playing anyways)
This is a bad idea, every network device has a different MAC address, so if you connected to wifi or Ethernet, you'd be stuck doing just that one way or face a ban or it wouldn't let you play. Filtering by IP is also bad, because people change modems, which gives a new IP, travel or visit friends' houses. So basically there is no good way to stop anything but the most obvious multi accounting. From a developers point of view, such stringent rules would reduce sales. Now the crpg team doesn't care about Warband sales, but when they go standalone, every multi account is another sale.