The challenges that they might have, in the US we do not use our passport to make a purchase. Essentially, the passport number is the only number to track those customers since many customers might have similar names or one customer may have several addresses and phone numbers. Even at that, I believe many customers might have two passports. Although, the worldwide system is implemented, there are many holes that Hermes cannot cover, not to count rules and regulations per district/country. I was thinking that only Hermes FSH can see the worldwide purchase history since it is the headquarter. For smaller stores, it would be very difficult to implement the system.