I'm trying to define in my head a problem I see with Bitcoin lightning transactions.

In the stores here that accept Bitcoin, there is a device "Tiankii" POS that is a smartphone integrated with a receipt printer. Small stores just have a Bitcoin wallet on someone's phone.

I don't know how they know which wallet is being used for the charge. It seems like they frequently have to hunt someone down with the wallet on their phone.

I often have this gnawing feeling of "have I paid?" I need some noise or flashing lights or something printed to assure the world Im not stealing this.

While trying to pay for something today, the one device was being shared with someone else's shop. So it was back to cash.

Problem: How to create a POS that is spread across smartphones.

I wonder if receipts could be Nostr Notes that could be zappable. I just want a Nostr note that proves I paid.

Would the store have an NSEC with a bunker key allowing each vendor's phones to be used to ring up receipts? This could integrate commissions easily with the zap sharing.

No more chasing down wait staff with machines to pay if they get a commission on their phone.