I've gotten fakes from Amazon, but it is not always obvious that you've got a fake.

There was an article recently with pictures of the real and fake items, both from Amazon. You wouldn't know which was which even if they were side by side.

But the fake will probably fall apart faster, may leak poison and is overall not what you thought to buy.

And that is all aside from the issue of fake reviews, which are so prevalent as to be the nrm. So the product might be an original, but it is not what you thought you were getting in way of reliability or noise et al.