Proof account hacked w/o keylogger

I now have proof that my daughter's account was hacked w/o a keylogger on any of my systems. About three months ago, my account was hacked while I was out of town on business. I bought authenticators for all three accounts in our house. I run Symantec end point security on all my computers and have a linux firewall. I scanned all our computers w/ AV and multiple Malware scanners. I even watched the netstat output to external sites while I logged into WOW. I found nothing. Still I accepted that there might have been something on our end.

My daughter's account has been inactive for over a year and we've never logged into that account via the game or any blizzard websites while the account was inactive. This morning my son was on his account and noticed one of her character online in his friend's list. I immediately changed the password and added an authenticator to the account and logged in to log the hacker out. They didn't delete or steal anything. They just took her lvl 70 hunter and dropped the professions and leveled up mining and herb to 450. She was in icecrown when I logged in.

This should be enough proof to everyone that this account was hacked w/o any form of a keylogger on our systems. They are either brute-force hacking into these accounts or someone has sold account info to the farmers.