Found an interesting tidbit.
I found this law today while reading through the state weapons regs. It effectively imposes responsibility on the seller to background check when selling a firearm.
Sec. 46.14. FIREARM SMUGGLING. (a) A person commits an offense if the person knowingly engages in the business of transporting or transferring a firearm that the person knows was acquired in violation of the laws of any state or of the United States. For purposes of this subsection, a person is considered to engage in the business of transporting or transferring a firearm if the person engages in that conduct: (1) on more than one occasion; or (2) for profit or any other form of remuneration.