List of Printers Which Do or Do Not Display Tracking Dots

The real question you should be asking yourself is how hard it is to fake these. If I get hold of someones copies, can I use them as template?

I think this is an excellent example of why security through obscurity is a bad idea. Now that we know they are there, it's only a matter of time before they are all broken and duplicated. How hard is it? I don't know, but I can't imagine that its impossible. Given time and technology, someone will figure how to forge these without difficulty.

They were clearly betting on the fact that no one would notice they are there. What scares me is we're just finding this out. How long have criminal organizations and rogue nations known about this and what have they used it for?

I'm confused about why people consistently think that this was a total secret, no matter how many waves of press coverage it gets.

https://en.wikipedia.org/wiki/Printer_steganography

There were press articles about it by 2004 (and I think some earlier), we had written the tool that Rob Graham used to decode these scans by 2005, and I gave a number of TV interviews about it during 2005. A small number of manufacturers (maybe worried about European data protection laws) also alluded to the existence of the technology in their user manuals. Some of the people from industry who contacted me also said that this was common knowledge to people in the printing industry since at least the turn of the millennium.

None of those are enough. Unless the spying feature is directly marketed to consumers, e.g. a TV ad that says "Buy a color printer THAT SPIES ON YOU today!", >92% of the population will never learn about it. (That estimate being from the # who don't read license agreements: https://measuringu.com/eula/)

Generally, anything that less than half of the population knows abut is a secret (e.g., menstruation is still called a "secret" in some circles...), so you shouldn't be confused, just disappointed at how gullible / uninformed the average person is.