1 that the value is gone is not a defense where money is obtained tortiously-- on what principle does it become relevant to a UE case?

2 yet there is something unsatisfactory about characterizing COP as based on an implied misrepresentation--- if $10,000 is mistakenly credited to the bank account of a person who has never seen $10,000 in her life, her position in a UE case is quite different from that of a recipient in whose account such an amount frequently appears at a time consistent with the challenged receipt?

so if UE is based on a misrepresentation, we get a better fit between legal words and the law by renaming the theory 'implied plausible misrepresentation'?

yet if there is any representation to be factually implied from a payment of money it is merely "i believe i owe you this'??

maybe it would be better to drop the fictional 'representation' out of the legal formulation: the rule is that the payee is not liable for money paid by mistake if she plausibly believed it to be hers and changed position accordingly? [i can see no principled difference between spending the money and forgoing an opportunity].