I decided not to use percentages for a couple reasons.
One, you could never completely rid somebody's bank account that way.
It doesn't really prevent anything, as they can just #fine again to get to where they want.
A fine database that used percentages based on the fine would be great if people were honest and never use a fake fine.
What it all boils down to is the trust--there'll have to be some when it comes to the coins. There's no way around it which leaves flexibility for all situations. Trust me.