You would need some sort of photo of their passport to verify citizenship for a foreign national. You would have to securely store thousands of these images for

You would need some sort of photo of their passport to verify citizenship for a foreign national. You would have to securely store thousands of these images for reporting purposes. It would be a legal and technological impediment and extra cost involving a large amount of effort for very little payoff. This was easier to limit with the online store. They just didn't provide international shipping options.