I think they are always negative. Including on bank notes.
I wonder if we could have a real, open and direct democracy. All the models we have right now work via indirect clowns. Then again, looking at how some people vote, perhaps direct democracy can only work if people are clever.
If checking for counterfeit bills becomes harder, trust in the currency is degraded. Once that happens, vendors will either incentive digital payments (which are definitionally tracked), switch to a tracked currency, or barter more. Trust in bills is super easy to take for granted.
Eh bank notes have watermarks just to make them harder to forge. They also have serial numbers, but as almost no businesses pay attention to them they aren't really used to track transactions. The provenance of a particular bank note isn't that interesting beyond knowing whether it's a forgery.
The problem with these spymarks is that they can be used to include data that's completely invisible to users - even potentially to sophisticated users and the programs that consume the marked files. So while I can make an informed decision whether to share a picture, I may not be informed about any spymarks. Vs a normal watermark that aren't designed to be invisible.
The problem with direct democracy is not that people are dumb, it is that they are incompetent.
To do politics right take skills, and I don't expect the average mechanic to be better at it than the average politician is at fixing cars. How should I know if we should subsidize organic farming, ban alcohol sale after 8PM, or increase the defense budget? At least in theory, politicians are professionals who deal with these kinds of questions, they are supposed to know the technical and social implications, or find experts to help them if they don't. Some people think they know, and judging by how stupid most of their ideas are, they don't. I don't blame them, it is just not their field, and my ideas are probably just as stupid anyways.