Look at the Citibank Revlon case from last year [0]. In a clerical error, Citi sent $900m to a bunch of hedge funds, related to some Revlon debt. It asked for it back. It got about $400m. It sued for the other $500m… and lost in court.

I’m not saying this is identical to that case, which depended upon New York law. But it is far from clear-cut and I think you are being way too confident in your view, since nothing like this has ever appeared in court.

[0] the decision: https://assets.bwbx.io/documents/users/iqjWHBFdfxIU/rrBrQQPB...