[jasonjei]

That’s a great point. In spite of technical changes such as Apple Pay/Android Pay, chip cards, and so on, I can never recall an instance when I was unable to use a credit card globally. It seems most failures to running a credit card are pretty localized, too, and never at the interchange level...

[raverbashing]

I suspect there's a lot of caching involved as well. When making a purchase you probably don't need all the info to go all the way to the bank and back.

Stolen/lost cards can simply be flagged in a master db/table and can be rejected quickly for example.