Just a few days ago (maybe a week ago?), Blizzard changed their transfer procedures. They realized how many times hackers/scammers would transfer chars off of accounts just with the last name, so, they now ask for the source account's answer to their secret question. I am not sure if they also ask for the destination SQ/A, but that doesn't really matter, since the destination account is your account anyway. This change affects both WoW US and WoW EU.
Just thought you guys should know; this does change scamming quite a bit. Before, you just needed to know someone's last name and their character could be yours. Now, you also need their SQ/A.