Autozone does sell parts that have been installed as new. Worked there 5 Years and have seen Management change Damaged Return Tags back to Undamaged many times.
These parts are then put back on shelves. Problem is, Management and District Managers only care about the Numbers. Company wide problem?..Sure it is. As long as they continue to replace Experienced parts people and good managers with fools, they will continue to sell the Public previously installed parts.
As a consumer, if this happens to you, report it to whatever state agency that handles consumer fraud complaints. It may be the only way to stop it.
Product or Service Mentioned: Autozone Manager.