No but they do have liability to perform background checks as per law before selling the firearm. If they do so, they are ok. If not, the law will go after them

No but they do have liability to perform background checks as per law before selling the firearm. If they do so, they are ok. If not, the law will go after them. This is not dis-similar to how GitHub has safe harbor as long as it follows the DCMA process https://en.m.wikipedia.org/wiki/Brady_Handgun_Violence_Prevention_Act https://en.m.wikipedia.org/wiki/Brady_Handgun_Violence_Preve...