They have a week to manually reset and update their email address. It is very irresponsible to setup an account and lose track of your throwaway email credentials. Any other accounts will be lost unless its a known member who can prove its them to theymos directly.

This would be a good opportunity to clear off many garbage shill accounts as well as they are more likely using fake email accounts.

Its not the end of the world if a few old anonymous accounts get frozen either and is a much better alternative than a bunch of compromised accounts start scamming people.

The hacked accounts make it pretty clear that either the passwords weren't salted,