This isn't completely accurate, it is illegal to KNOWINGLY sell a firearm to felon or other prohibited person, or to KNOWINGLY sell to a resident of aother state.
The key word is knowingly.
There isn't any law that requires you to investigate the home resident state or the legal status of a buyer in a private firearm transaction.
As a side note there is a long list of reasons a person maybe a prohibited person, (felon, domestic violence conviction, currently under indictment, in the country illegally, adjudicated mentally ill, dishonorable discharge from the armed service, the illegal use of controled substances, etc).
That idea that having one show a state ID and or a WCL by no means proves that the buyer isn't a prohibited person, it just gives the seller a false sense of security...
You kinda jumped in the middle of something. Maybe you should have read the entire thread?
The KEY word is BUYING
It wasn't about knowing anything. It was about, "Why is it all on the seller, and not the buyer"?
If someone under the age of 21 buys alcohol from a store, the store gets the $$fine$$, the person that initiated the crime, gets off with "don't do that again"
Is it illegal for someone to buy from someone out of state?
(let's assume that the person going to another state to buy a firearm knows that they are not a resident of that state.)
Is it illegal for a felon to buy a firearm?
(let's just assume that the felon, knows he's a felon)
Why is it illegal for a felon to be in possession of a firearm, but not illegal for him to buy a firearm?
It's a crime for Joe Citizen to lie to Law Enforcement, but Law Enforcement are encouraged to lie to Joe Citizen.