Citibank just got a $500M lesson in the importance of UI design

I don't even have anything to add. The paragraph speaks for itself... You can't make this up

As per Matt Levine's article [1], referenced by Ars:

Much of the dispute in this case is about whether “the recipient[s] did not have notice of the mistake,” that is, whether the lenders should have known, or did know, that the wire transfers were a mistake when they got them. They argued that they had no idea anything was wrong, that the payments were the exact amounts they were owed, that they assumed Revlon was intentionally paying down its loan ...

Once Citi did send the recall notices, of course, the lenders knew it was a mistake, and they all sent each other chat messages making fun of Citi. ...

... the judge points out that these chats only happened after the recall notices went out, and “the number and nature of these communications reinforce why the absence of such communications before the Recall Notices is so significant.” That is, if the lenders had thought the payments were a mistake when they got them, they would have been unable to resist hopping into a chat room and cracking jokes about Citi, as proven by the fact that when they got the recall notices they did all crack jokes about Citi. The fact that they didn’t make any jokes for almost a full day proves that, when they got the payments, they thought they were legit.

[1] https://www.bloomberg.com/opinion/articles/2021-02-17/citi-c...