And what if it were 1M? 500M? 1B? They just go out of business? Your logic doesn't scale well and seems overly harsh. They offered $500 and a pair of tickets. The guy lost nothing, I think that's fair.
I'm certain I wouldn't considering I've spent my entire career in cancer diagnostics and finance.
This is a completely reversible mistake and no one was harmed in any way (feelings don't count). Let's not go off the rails and start making Therac-25 like comparisons. This isn't some abstract problem; the issue is well defined, so let's stay within the realm of reason.
And how do you propose that would be done? You've totally jumped the shark here. Comparing this, an easily reversible incident, to HFT is simply nonsense. Thousands (probably a lot more?) of transactions would have occurred within the context of the bug, and decisions were made based on bad data once the bug was in the wild. There's no way you could undo that.