"If you go into a baker's to buy a bun and they give you the wrong change and you walk away knowing you have been given more change than you handed over in the first place, that's theft," Sara Ludlam, an intellectual property expert at Lupton, Fawcett, Lee & Priestley told the BBC.
What? That's not true. It's the merchant's responsibility to not fuck up. You have no legal obligation to correct them.
You'd think a fucking lawyer, even a joke (IP) lawyer, would know that.
Well, it's been many years since I practiced law, but I DID practice in criminal law, and sorry but she's right. The key is whether you know you've been given too much change, and whether you knew it at the time that you left the store. Fraud would be an easier fit (it includes deception by omission, so long as you're (a) aware that the person is deceived, and (b) someone is getting a financial benefit), but theft would still apply.
Common assumption of blameworthiness =/= the law.
As a general rule (not universal, but a good rule of thumb) criminal law works on intent, not action - so it usually doesn't matter if you received the money via an act or simply an omission, so long as you formed the intent to leave the store with the money.
In a practical sense, however, you wouldn't get charged because there's simply no way of proving that you knew you were given too much change, and hence no way of proving intent. Even if it was a large amount of money, you could always say that if it was possible for the shopkeeper to accidentally miscount, then it's equally possible for you to have done the same.
Also, I certainly wouldn't call IP lawyers joke lawyers. Sure, IP law itself is grossly unfair, but it's also one of the more complex areas you can practice in - hell, it's a fuckload more complex than criminal law is. Given that IP lawyers (except patent lawyers, who aren't actually lawyers but scientists - lawyers aren't actually permitted to advise on patents) usually also need to know trade practices law (anti-monopoly, misleading and deceptive conduct, etc) I'd actually rate it as the second most complex area of law to practice in after tax law (and by tax law I'm talking large corporate clients - small business tax law is a piece of cake compared to IP law).