The specific issue in the relevant wired article wasn't the policy and devices that are in use, but the abuse and mis-use of the policies and devices by TSA-hired agents. If the TSA is unable or doesn't choose to monitor and eliminate this behavior in its employees, but a private company does, then their could be a distinguishable, competitive advantage. In other words, allowing agents to request extra body scans of particular people they want to see (hopefully) isn't a policy mandated by the TSA that a private agency just can't avoid.