This has gone very off topic...
Has CJ ever said why they made the rule that pirates can't own Banks, I'd be interested, as for mechanics being real life or not,does it really matter? Most mechanics are thought from real life and then modified to fit the game better, but some mechanics are completely separate from real life.What you need to think is what are the effects that this change would have on the game, an whether those effects would be positive for the game or not, (for the game not singular people).
In my opinion, automatic payments should be stopped and interest should not be added for not paying back(if bank is closed)(as it is) but you can manually pay back the loan if you wish to. As for the banker earning a little amount of money when his bank is closed? Is that really a massive problem? and for those people who aren't annoyed about loans you cant pay back don't have to pay them back till the bank is reopened.