While I understand and agree with the premise that a store operation can refuse to ship anything as agents/ representatives of a private company, I don't think they can do it as agents of the USPS. Of necessity, they wear two different hats--one for UPS/ FEDEX ETC and one for the USPS. I'm not sure but I would imagine their respective contracts are way different with the private companies vs the USPS. I'm going to guess that's why the sign stating they would not accept firearms for shipment came down. If they were to be a store front representing the USPS, they would have to abide by the pub'd Postal regs.
