A googler told me that's approximately why — long-disused accounts were overrepresented among abused accounts. In particular he mentioned that accounts that had

A googler told me that's approximately why — long-disused accounts were overrepresented among abused accounts. In particular he mentioned that accounts that hadn't been used in a long time were much more likely than the average to have a poor password. To crack down on abuse, they try to force the affected users to become aware of their accounts.