> There are legitimate uses for the product and it isn't immediately apparent to the store why someone might be purchasing a given item. It's not their job to invade their customer's privacy.
You seem to be implying that nothing is ever legitimately fair use.
> Your logic regarding torrents only works if we assume that a significant number of peers are engaging in fair use.
What evidence do you have that this isn't the case? Not evidence that someone is doing it for the wrong reasons, evidence that no significant number of people are doing it for any legitimate reason.
There are a lot of things that are plausibly fair use. If you subscribe to a streaming service with a plan that includes 4k content but their broken service won't play that content on your 4k TV, can you get a 4k copy of the thing you're actually paying for? If you're a teacher and the law specifically says you can make copies for classroom use, but the copy you have has copy protection, can you get a copy that doesn't from someone else? If you're an organization trying to make software that can automatically subtitle videos based on the audio so that hearing impaired users can know what's being said, and you need a large amount of training data (i.e. existing video that has already been subtitled) to do machine learning, can you get them from someone else? What if you're an archivist and you actually are making backup copies of everything you can get your hands on to preserve the historical record?
What alternative do such people even have for doing the legitimate thing they ostensibly have a right to do?