Based on your financial expertise, provide your response or viewpoint on the given financial question or topic. The response format is open.

Gigantic point amount on rewards card - what are potential consequences?
What would be the consequences if they do realize their error some day   in the far future? You've informed them of the error and they've informed you that nevertheless the points are yours and you should use them. So you have a couple of issues: have you made what your jurisdiction considers a reasonable effort to correct the mistake, and did the customer service rep actually have the authority to make such a large goodwill gesture as letting you keep all the points? The first is your legal responsibility (otherwise you're stealing), and you need to know specifically for your jurisdiction whether a phone call is sufficient. I can't tell you that. Maybe you should send them a letter, maybe you should wait until you've had written confirmation from them, maybe you're OK as you are. You might be able to get free advice from some body that helps with consumer issues (here in the UK you could ask Citizen's Advice). The second is beyond your ability to know for sure but it's not dishonest to work on the basis that what the company's proper representative tells you, is true. With the usual caveats that I'm not qualified to give legal advice: once told you've been clearly told that it's an intentional gift, I don't see any way you could be held to have done anything fraudulent if you then go about enjoying it. The worst case "far future" problem, I would expect, is that someone decides the gift was never legitimately made in the first place. In other words the company made two separate errors, first crediting the card and then telling you the erroneous points stand. In that case you might have to pay them back whatever you've spent on the card (beyond the points you're entitled to). To avoid this you'd need to establish what constitutes a binding gift in your jurisdiction, so that you can say "no, the point balance was not erroneous and here's the legal reason why", and pay them nothing. You might also need to consider any tax implications in receiving such a large gift, and of course before paying tax on it (if that's necessary) you'd probably want to bug them for confirmation in writing that it really is yours. If that written confirmation isn't forthcoming then so be it, they've rescinded the gift and I doubt you're inclined to take them to court demanding that they stand by the words of their rep. Use them and play stupid. It's not my duty to check their math, right?  That's potentially fraud or theft if you lie. You did notice, and even worse they have proof you noticed since you made the call. So never say you didn't notice. If you hadn't called them (yet), then you've been given something in error, and your jurisdiction will have an opinion on what your responsibilities are. So if you hadn't already called them, I would strongly suggest that you should call them or write to them about it to give them the opportunity to correct the error, or at least seek assurance that in your jurisdiction all errors in the customer's favour are final. Otherwise you're in the position of them accidentally handing you their wallet without realising, and you deciding to keep it without telling them. My guess is, that's unlikely to be a legally binding gift, and might legally be theft or fraud on your part.