Would it be a problem for the system to simply adopt a variable interest rate based on the SD supply and market cap?

Also - as users leave the platform or lose passwords, what will happen to any SD in their wallets? Could those auto-conversions be high enough to essentially wipe out an account's SD holdings if they were sitting on, perhaps, $10,000 SD? What could an auto-conversion look like for inactive user accounts? A percentage of holdings over a specified time frame?