[nulbyte]

Actually, merchants, acquirers, and issuers can do this. It happens sometimes. When it happens, other limits come into play downstream, such as terminal configuration. There are separate offline limits, and it is unlikely they would set it that high, so a $20,000 offline charge would be declined, even if a lesser charge would be approved, stored, and processed later. As for expired cards, the expiration date is on the mag stripe and in the chip, so the transaction could be rejected at any point, even offline at the terminal. It's also printed on the card so it might be rejected before it's even swiped or dipped.

[lathiat]

It's even done regularly in some cases, various US airlines take "offline" card transactions and process them later for food & drinks.

There are of course limits on how big an offline transaction you can take intentionally or unintentionally and probably the airline wears the full cost of failed transactions in this case.

Doesn't matter that much when its for a $5 coffee, plus they know who you were if they really wanted to chase it down.

And as mentioned electronic terminals absolutely have automatic offline modes also.