In most cases it's not fraud but easily explicable. Many resellers buy wholesale old boxed versions from across the world, which can no longer be sold in the retail stores because the label on the box no longer states the actual year, but of course these licenses are still good for activation.
For example, if I want to activate the German version of KIS 2015 I can do so with the keycode from a two year old Polish or Italian boxed version with an inch of dust on it. This is why most licenses are so cheap, not because of fraud. Of course Kaspersky wants me to pay the fantasy prices on their homepage and that's why they are suggesting through the grapevine that I could become the vicitim of fraud.
Of course there is always the possibility of fraud, but even if two out of three bought keys are going to be blacklisted and I have to buy a third one, it's still cheaper than the fantasy prices on their homepage. I for one have been buying keys for AVs on ebay for years and not a single one has been blacklisted yet, even though the scoundrels from that blog page are suggesting otherwise.
In my opinion it's a despicable borderline criminal act to put the entire second-hand market under the general suspicion of fraud. Typical AV vendor scare tactics, if you ask me, though in accordance with the best traditions of this business.