Well first of all, just to put it out there, it really doesn't matter how much support the suggestions for the same exact feature get, Ched has already stated he wants protecting money to be more difficult, not easier, and the faction vault was never intended to be used as a personal bank, despite the fact people continue to do so.
With that out of the way, you probably didn't realize it, but you actually kinda answered the very dilemma you brought up.
should the faction vault be where they store their money? Absolutely not. But no matter how much you tell people they won’t store it elsewhere.
True. Similarly, no matter how many times people suggest this and get shot down by Ched, people will still ask for it.
Since being given a role with banking privileges in my faction I’ve spent probably the majority of my time just filling banking requests. Even when I am unavailable to fulfill them I’m getting spammed with private messages asking to withdraw a couple thousand of their millions stored in the vault.
Make em wait, don't respond, or if you don't want to deal with it, ask to be removed as a banker. Clearly you don't enjoy doing it, so why are you a banker to begin with? Regardless, if players do banking requests, fulfilling the request is delayed, and they get upset, it's kind of on them, not on you or any other banker. There are other options for storing your money. If we're going purely on efficacy and not on how these things actually work, players shouldn't ever need to store more than 85m in the faction vault. Once you hit 85m in cash, you can afford a palace and a small vault, which can easily ramp itself up to an extra large vault without ever needing to store money elsewhere. Leading up to that 85m required to purchase those, there are other options for hiding your money. Piggy bank, ghost trade, stocks, products (like xanax), points, there's plenty of options, and many of them granting immediate access to your funds, though sometimes with a cost associated. Making the faction vault a 24/7 ATM is entirely unnecessary, and, as mentioned, not in Ched's plans for the future.
#chedging