I think your argument was pretty good however you did make one statement that I disagree with which has made many firearm seller overly fearful when meeting a buyer. Your statement "However, most responsible gun owners want to somehow make sure that the person they're selling a gun to is legally allowed to own a gun because selling a gun knowingly or unknowingly to a person not otherwise allowed to own or legally possess a gun is a felony." is untrue!
The actually law reads (Quoted from the ATF Federal Firearms Regulations Reference Guide 2005 - received in 2012 with my FFL-03 license) "A person may sell a firearm to an unlicensed resident of his State, if he does not know or have reasonable cause to believe the person is prohibited from receiving or possessing firearms under Federal law. "
As I interpret it, this means as long as you see a drivers license that verifies the buyer is over 18 and a resident of Indiana, unless he is intoxicated, or show clear signs that he is mentally unbalanced, you are perfectly legal to sell to person. I don't think anyone here having "reasonable cause to believe they are prohibited" would sell to any buyer! So even if they turn out to be a terrorist or Felon, you cannot be held liable.
However I don't think anyone here selling a firearm is likely to meet buyers that are not legal to possess firearms. There is too much chance that the ATF or local LEO's may become involved in the sale. The criminal element is far more likely to purchase firearms from other criminal elements, or steal one etc., than to arrange a meeting over the internet and risk arrest.
The actually law reads (Quoted from the ATF Federal Firearms Regulations Reference Guide 2005 - received in 2012 with my FFL-03 license) "A person may sell a firearm to an unlicensed resident of his State, if he does not know or have reasonable cause to believe the person is prohibited from receiving or possessing firearms under Federal law. "
As I interpret it, this means as long as you see a drivers license that verifies the buyer is over 18 and a resident of Indiana, unless he is intoxicated, or show clear signs that he is mentally unbalanced, you are perfectly legal to sell to person. I don't think anyone here having "reasonable cause to believe they are prohibited" would sell to any buyer! So even if they turn out to be a terrorist or Felon, you cannot be held liable.
However I don't think anyone here selling a firearm is likely to meet buyers that are not legal to possess firearms. There is too much chance that the ATF or local LEO's may become involved in the sale. The criminal element is far more likely to purchase firearms from other criminal elements, or steal one etc., than to arrange a meeting over the internet and risk arrest.