The timing of this thread is kind of funny. Over lunch, I was in a local pawn shop and saw a guy try to buy a gun. It was a 16" Bushmaster with what I think was a muzzle brake (vent holes were only on the top half) and real collapsible stock. I'm not an AR-15 expert, but I was surprised by the $1040 total and the shop owner claiming such guns were hard to find. Evidently it had been on the shelf for less than 24 hours.
On topic, the buyer tried to pay with a credit card, but was initially refused. The checkout guy dialed in and in the process of trying to get the purchase approved answered the question "what is he buying?" with "a firearm". My jaw dropped, and I think the buyer was a little perturbed. They asked why that mattered, but I didn't hear the response.
I've never seen a credit card company endorse the right to privacy. I do my best to not give them my business, but when I do I assume that they are collecting as much information as they can.