I don't think it is right to expect Bushmaster to enforce the license that the government issued. Bushmaster has every right to expect that the government did due diligence when issueing the license. If Bulls Eye was negligent, it was the responsibility of the government to pull their license, not Bushmaster to investigate the compliance of a duly licensed vendor.
The fault is the government's, not Bushmaster. The process should be for the government to revoke the license when they find that the dealer failed to comply with regulations. Vendors should be able to expect that a license holder has been certified by the government and that it is safe to do business with the license-holder.
-PJ