i've never been hacked either but for the most part nothing is placed in our guild bank that isn't free for anyone in the guild to take. I only use it to transfer an item to a guild mate, I transfer between my own accounts directly without even using the bank. essentially, our guild bank only has junk in it and less than 1k gold.

if we had our guild bank hacked we might not even know it until the hacked person spoke up.
make your dead beat brother get an authenticator