With a lot of cards and a lot of gas pumps, when you swipe your card at the pump, the pump pre-authorizes $100 on your card, and then settles the transaction for the amount you pumped.
At the bar, you'd deposit an amount of Bitcoin, and then get your change back when you settle your tab.
If somebody solves mobile in-app lightning nodes, then it could entail opening a channel with the bar at the beginning of the night and settling it at the end of the night.
So far the immediate, not really technical solution that I’ve thought was a deposit that is returned upon closing. Curious on the channel idea though. Are you speaking on opening a, say, 1m sat channel to the bar’s node, directly using that channel, then closing the channel to return local balance? That sounds like a really good idea, with a byproduct of kinda putting a limit on your spending for the night too. But the major downside which I would assume to be the mortal blow is opening a channel. Think the time and fees may not be ideal or attractive if the mempool is not in a good position.
Yeah I was trying to think of a way to avoid committing funds on chain one direction, and then sending funds back the other direction thus incurring 2 Tx fees.
Just don't close the channel immediately. Maybe keep it open and let it route sats until fees are low enough to close the channel.
Or be a consistent customer and visit the bar again later and spend more.
