When you pay in cash you usually get a receipt.
Usually aka 100% times in a civilized country and not in a 3rd world slump.
That is your proof you have paid and this is how things work fine for ages in Europe.
If the cashier is handing you the wrong change and denies taking your money you can of course call the police and have the cash in the machine searched and counted. We have a law in place here that while working as a cashier you are not supposed to have more than the equivalent of 5 euros on you.
I live in what you call a civilized country and not from Tier 3. And you don't get a receipt everywhere, today I bought cigarettes no receipt, then I've been to the bakery and butchery still no receipt. In the daily routine, I get a receipt at the supermarket only.
If you think the police will come to the supermarket because the cashier did an error or something like that then the police has maybe nothing to do in their office, because so far if you try here they will just laugh at you.
Yes, cryptos resemble cash. But:
- You don't use cash (or gold) for large "unattended" transactions. Do you buy with cash a 1000 usd / eur product in a dark alley when nobody else is present? In a transaction with other witnesses where the seller claims "You haven't paid for this" I can ultimately seek protection by law. I cannot say this is my banknote but I can try to prove that I have paid.
- You cannot use cash or gold for not face-to-face transactions.
You don't use gold to pay a transaction, I was referring to the old time when money didn't exist.
Why couldn't I pay a $1000 product if nobody is present, I don't need a witness. I make a deal with someone the person sign a letter confirming he sells me this and that and that's it.