But let's be honest, weird transaction glitches happen with fiat too, so it's not really a bitcoin-specific thing.

For sure, it was definitely not a bitcoin thing. It had to do with what happens when square voids invoices as they’re being paid. I don’t blame them either. It’s just the nature of nascent technology.

If I were the customer, I'd want to pay again, and if I were the restaurant owner, I'd want to let the customer off the hook

You’d fit in well around these parts. ;)