It's very cut and dry, and solely based on the first and last name of the person who originally registered the account. If your name is different, and they investigate, they will ban you. I personally don't see the harm, but it's not my rules. We're not supposed to discuss it here, but if you last names are the same, you might get lucky, but IMO it's not worth it. I know, it sucks, and its expensive, but it will be more expensive if you level 3 toons to 80, and get all 3 accounts banned, and having to start from scratch. Just pinch some pennies, and buy a new battlechest. And you don't need to buy TBC or WOTLK for that matter until you hit level 60-70, or if you want to play the types of toons available to those expansions. Spreading stuff like that out always makes things easier.