We're mostly not, but our NCOA process is designed such that instead of just editing the current mailing address, old addresses are inactivated and then flagged using special contact point purposes to explain their history (either "NCOA Move" or "NCOA Delete"), with a third option ("Bad or Unknown") to be applied by staff when inactivating an address. Not a sanctioned use! But we are looking in to whether we have any applications for them, and if so, how to manage them.