One way to restrict sales would be to require the sale to be performed via the Apple Store app on the customer's iPhone, with a limit to the quantity purchasabl

One way to restrict sales would be to require the sale to be performed via the Apple Store app on the customer's iPhone, with a limit to the quantity purchasable on a per-iPhone-per-year basis. Not offering any kind of general product support (other than required for warranty support) would also be a significant inhibitor for many people.