I don't know if this is an oversight by Blizzard or what, but if you got banned and dearly miss your pets and achievements, create a 'starter edition' account on the same battle.net account. That's their 'free to play to level 20' forever bit. I did that, and when I logged on, my achievements, titles, and pets from my banned account were there. My characters are gone, but those things still remain. And don't bot on this new account - Blizzard has something going that catches bots regardless of bot type. A family member bots with PocketGnome, and she had her accounts banned as well. It's just not safe any more, at least not for gathering. As an added bonus - every time you log on to the starter account, there's an 'Upgrade to WOTLK for $5!' offer.
Yeah, good to know. Also - mounts and titles are preserved, as well. Making a free account costs nothing, so if you're qq-ing over your loss, it won't cost you anything to try.