How quick are the stores to marking their status as Closed? It's manual I'm assuming and not some service that's not getting a pingback because the store is offline.
Can a modern restaurant function without internet access to handle credit card transactions?
Yes. You can imprint the card and/or record the information for offline processing. We had credit cards before everyone had internet access.
What about the percentage of people who no longer carry physical cards and rely on a smartphone/smartwatch credit system?