I only a run the local guild. But, even I don't give anyone full access right away unless I know them, or know 100% that they aren't going to take everything. If I don't know them, or know of them, they go on restriction for a while. I don't feel bad about that. If I was running a larger guild, it would be even more important to be careful. That's just how I see it.
PC-NA - formerly, mommadani907Guild: Weeping Angels - Co-GMTwitter: @ Loralai_907 several Alt accounts....CP 1700+
Only put stuff in that you no longer want, and can handle losing.
As for the player cleaning out your bank, well... That's bad recruitment on your part. You should only give permission after the player in question has shown enough loyalty that you can trust them.