Oh, I know you can transfer large sums of money person to person without issue. The vast majority of my cash has usually been either on my main or my bank alt, so I've had to transfer up to 7k each to 4 other toons at a time {flight + epic flight + cold weather flying + spells/respecs and such} several times.

I just know that transfers of large sums of money can raise a flag on your account. I should have elaborated that it can draw attention to transfer money person to person or via the neutral AHs. Guild bank, transactions, however, probably shouldn't. Especially if they look at the account/toon the money was coming from and going to...they would all be his and that should have negated any suspicion that he was buying/selling gold.

And yes to the authenticator. I literally slept better at night knowing I had one on my accounts. More than once I had nightmares about waking up and finding someone had pilliaged my guild bank and my personal bank. I just wish all games had them!