Maybe you can add this to get rid of inactive accounts:

Users that don't log in to the site for 2 years will be deleted automatically.

I mean, who would get back to a site they left 2 years ago! (That is so rare!)

Something like this is already in place. kirkq removes accounts if someone requests the name and the account has been inactive for a year with no runs. It's not done automatically (no need to auto remove accounts), but something similar to your request is done.

the runs aren't gone when your account gets deleted on here, they'll just be displayed as if you've never registered.