Even financial markets will do it as needed. I used to write trading software. Some of our traders were trading on the DTB; being German, they were sticklers for rules. One day our traders jumped on something and made a lot of money. But it turned out that somebody at another company had fat-fingered an order at a very low price for a very large quantity. Large enough that it would have destroyed their company.

The exchange decided there was no point in that, so they unwound all the trades. I thought our guys would be mad. They were a little disappointed to lose the expected profit, but they were otherwise fine with it. They didn't see any sense in that kind of destruction just for a short-term gain.