Well latency wouldn't be an issue with 2 cable internet connections... I've actually used WoW like this at work once haha.

As for being overly paranoid... this may be so. I just really don't want to get this guy banned. I mean, if he did get banned, it would be obvious that it was my fault as I've heard that they list that they saw multiple IPs in the email that you receive.

You do have a point on the internet cafes/vpns/hotspots. I'm going to look into people that have been banned for using another persons account on a separate IP before I get to boosting