Once upon a time, I worked on behalf of a few luxury goods makers, tracking down counterfeit versions of their items, and getting the obvious and less obvious fakes removed before anyone could waste money (and their perception of the brand) on them.

A few times, I would be invited to company HQ and introduced to the product, have the stitching and design details explained to me, a lay humble scruffy programmer. I can still spot a quality handbag from miles away because of it.

The work itself was _fascinating_ to me, and spotting fakes was... obvious but only once you knew _why_ it was obvious. A couple of examples:

* (easiest) Does brand X make phone covers? Well, probably not because that would make them look cheap and accessible to all, and that's _very much not_ the point of being a luxury goods house.

* (... tricker) Are there _any_ loose stitches visible, or imperfections of any kind? If I had been thinking logically, this wouldn't be an issue. But, like the buyers, I hadn't been, and I hadn't realised that -of course- luxury goods are hand checked by many people, many times over, because... again, that's the whole point of being a luxury goods house.

While there was plenty to learn about mismatched parts - plus the joy of independent designers creating new and sometimes quite brilliantly designed new items (always a shame, some of them knew the brand styles staggeringly well) - looking at the zips that match a leather which match so-and-so design element, the examples above covered the majority of counterfeit items by far. Can't imagine it's changed that much in the meantime.