How about asking the security question when logging onto a unfamiliar computer/ip address?
Fantastic idea!

So long as they reset people's questions whenever they implement the update, because I'm fairly certain I don't remember what my question/answer was, and I'm willing to bet I'm not the only person.
Let's hope... because I don't know if I remember mine exactly.
I think your question's a bit
TOO secure, if it won't even let
YOU in.
It's in your preferences. An option to reset it or reconfigure would be a good addition as well. Should require a support ticket to change the security question.
Great addition to the idea.

I don't think that we EVER needed to untag something very quickly - and when it comes to gold withdrawals, since the main goal of the restriction would be to prevent structures from collapsing, it sure wouldn't be a problem to make some compromise, i.e. 20% of the guildbank could be withdrawn immediately and the rest with 12-hour lock.
Good addition to the initial poster's idea.

I would stretch it up to 30%, personally, but that's something that could be hashed out.