Who is your customer?

I'm taking the chinatown bus back from NY to Boston on Sunday (trip took 6 hours...ugh) when I catch sight of a billboard advertisement.

GUNSHOW!! WE SELL GUNS!
NO ID REQUIRED. NO BACKGROUND CHECKS.

First a disclaimer. I'm pro gun-control. It seems like everyone would be safer if no one had a gun (except the police). Now what troubles me about this advertisement is the fact that they seem to be targeting a specific market. Obviously they are advertising to:

1) People who want to buy guns;

2) Additionally making it clear that they can sell to people who don't want ID checks or background checks.

It seems to me that the people who fit into 2 are:

2a) People who want guns quickly and don't want to wait for checks;

2b) People who wouldn't pass an ID check or background check.

Now it seems wrong to be selling guns to 2b, and to be advertising to them so blatantly just seems to run contrary to the good of the general citizenry. If I sell a gun to someone who I know will do something bad with it, I should be held responsible for the consequences if they are forseeable. I'm not sure you can make that argument with sales at gun shows, but the advertisement (while factually true and giving correct information) seems to appeal strongly to people we might not want to have guns and could expect to do bad things with them. I'm curious about the legal liability implied by gun sales. There was a Law and Order episode about guns that could be easily turned into automatic weapons, but I don't know any actual case law.

[/XX comment]:
Are you talking criminal liability or civil (tort) liability? (I don't know anything about criminal...)

Putting aside the 2nd Amendment issue here, I think one could make a strong argument that there should be legal liability for gun sales - at least those conducted without an ID or background check.

First off, aside from any statutory requirements there may be for background checks, the burden of taking these ID/background check precautions are miniscule. You plug the name into a database. You make the customer wait. These aren't particularly burdensome. (Though a libertarian may argue that the restriction on your freedom is, in itself, an unacceptable burden.)

The probability that harm would occur without such precautions is more debatable. This one could go either way, though I think it weighs in our favor. If, as you said, advertisements like the one you cited tend to draw group 2(b), then a reasonable person could foresee that serious harm - will result from the sale of the gun.

But there may be more debate there than either of us may want to admit. I mean, how far down the stream of foreseeability do we want to go?

If a gun dealer sells a gun to someone without an ID check, then that person's toddler son finds the gun, gives it to a friend, who shoots a valuable show dog that accidentally wandered into his backyard, do we want to hold the gun owner liable? What can we say is reasonably foreseeable? Is the gun dealer in the best position to make that call?

Taking this debate to another realm, the foreseeability argument was also used in an attempt to hold manufacturers of VHS recorders (and, more recently, Napster, KaZaa) liable because their products could foreseeably be used to break copyright laws. VHS recorders might be a different story, but if you make the argument that the only real foreseeable purpose of guns is to kill or hurt people, you might also have to concede that the only real foreseeable purpose of Bittorrent is to facilitate Internet piracy.

I'm just rambling now, ... having made no points directly addressing your interesting question. ;)