Or 82 billion, or trillion... yes, I would expect them to go out of business. Same if they made a mistake that killed someone, for example. As others have said, what if the client (or they kid!) had made the bet online and entered a few extra zeroes (and lost) - would they have accepted "I made a mistake" as an excuse and canceled the bet?

You should not encourage a business to have a "head we win, tails you lose" policy.

But a client entering a couple extra zeroes is not a clean and obvious mistake. A person could reasonably bet either $5 or $500 for example.

On the other hand, offering something like a 1000x payout for an event that has a 50% chance of happening is a clear and obvious error.

If an error is egregious and obvious, it seems reasonable that a company (in this case FanDuel) not honor the deal.

Similarly, say a grocery store meant to have a "Buy 1 get 2 free" steak sale but accidentally keyed it in as a "Buy 1 get 200 free" sale. Nobody would expect the grocery store to actually give away 200 free steaks to every customer who bought a single steak.

> But a client entering a couple extra zeroes is not a clean and obvious mistake.

Neither is an oddsmaking posting odds out of line with your perception of thpe likelihood of events—if you are gambling, that's exactly what you are looking for normally.

> If an error is egregious and obvious, it seems reasonable that a company (in this case FanDuel) not honor the deal.

This bet was made over the counter: if there was such an obvious and egregious error, it should have been refused at the counter. Would FanDuel have tested the bet induced by the odds as null and returned the funds if the bettor had lost? If not, why should it get to nullify it when the bettor wins?

I am pretty sure that would fall under pricing error laws,and at least in California, they would have to honor it.

Yes. How is it different from the software error that led to $440 million loss for Knight Capital Group (https://en.wikipedia.org/wiki/Knight_Capital_Group#2012_stoc...)? I bet they would love to cancel the trades they executed and get a refund as well.

> Whenever there's doubt side with the customer but this was such an obvious error that any reasonable better would have realized it.

But, essentially every bet is exactly the bettor assessing that the odds represent an assessment of the likelihood of an event that is wrong; from the bettor’s position gross errors of the market (the other bettors whose actions are the input to odds-setting) that they should mercilessly exploit are indistinguishable from gross errors of the aggregation system which you suggest they should not.

Especially with a human-in-the-loop system for taking bets, the protection for the oddsmaker should be that their agent refuse to accept bets when there is such an “obvious(ly attributable to the odds-setting mechanism) error”.