I do believe that you get to keep cash. I don't think I've ever heard of an instance of "dirty cash" getting seized back from a merchant. Do you have an example of that?
No, but I don't really have an example of a specific credit card chargeback, either. At least in the US, the police can seize the cash as evidence, and their duty is to return it to the rightful owner, not whoever happened to have it at the time of seizure.
There is plenty of evidence that credit card charge backs are a thing, I don't think anyone would challenge their existence.
> At least in the US, the police can seize the cash as evidence, and their duty is to return it to the rightful owner, not whoever happened to have it at the time of seizure.
They do this with cash found in possession of criminals or suspects but do they do this with third parties not involved in crime? If someone unknowingly sells a car or a house to a criminal, can the cash they received for it be seized? What about legal fees. If a lawyer was found to have been paid with "dirty" money, can the cash be seized? What about cash spent at supermarkets? At the hospital? Etc. I've never heard of such a thing which is why I was asking for an example.
The only concrete example I could find is https://www.nbcnews.com/id/wbna26959902 (though to be fair my research here consisted of checking the references on the Wikipedia page for "Marked Bills").
The important thing to remember here is that possession of stolen goods or cash is a crime (cf for example https://www.law.cornell.edu/uscode/text/18/2315), so if it becomes known to you that stolen cash is in your possession, you have a legal obligation to give it back. Given how fungible cash is, this probably won't be enforced if somebody uses stolen cash to pay their bill in a restaurant, but it probably would be if someone bought a car with cash that could be traced directly back to a bank robbery.
Since bitcoin is infinitely more traceable than cash, the argument of "but how do you know this particular dollar bill was stolen?" wouldn't really be applicable.
