The Cost Was Never in the Word
"Organic" used to mean whatever the farmer said it meant. No inspector, no seal, just a hand-lettered sign at a roadside stand you drove past every week.
That should have been a terrible signal. A costly signal works because faking it costs more than having the real thing does: a peacock's tail, a wedding ring you can't take off in public. A word painted on plywood costs nothing. Anyone could write "organic" on a sign whether or not it was true.
The reason it worked anyway wasn't the word. It was the size of the room the word was spoken in. The farmer sold to the same fifty households every Saturday, some of whom drove past the field on the way to work, some of whom knew the guy who supplied the seed. Lying was possible. Getting away with it, in front of people who could just look, was not. The cost that made the claim credible sat outside the claim entirely, in the reputational bill that came due the moment somebody checked.
That's a different mechanism from a costly signal, even though it produces the same result. Call it a policed claim: cheap to make, expensive to fake, but only because the population able to catch the fake is small enough, attentive enough, and connected enough to actually do it. The claim is free. The policing isn't, and somebody's paying for it, mostly the claimant, in the form of a permanent audience with standing to catch them.
The arrangement holds exactly as long as the room stays small. Once "organic" started selling into supermarkets three states over, to buyers who had never seen a field and never would, the policing population didn't shrink, it disappeared. Nobody in that chain had the history, the proximity, or the reason to catch a lie. The word on the label cost the same nothing it always had, but the thing that used to make nothing-cost credible was gone. So the claim, which had been meaningful for free, became meaningless for free, and somebody had to go build a machine to manufacture the missing cost back: inspectors, paperwork, a certifying body, a fee. USDA Organic is a paid replacement for the relationship that used to do that checking for free.
"No AI used" is running the same arc, earlier. On a blog with a few hundred regular readers, the disclosure works, not because it's hard to lie in four words, but because the readership is small enough to have a memory. Someone who's read a writer for years has a feel for their sentences, their tics, where they trail off, what they'd never bother to say. A sudden smoothness, a paragraph that resolves too cleanly, gets noticed by people who carry the back catalog around in their heads. That's the policing. The label is free; the readership able to catch a lie about it isn't, because building that readership took years the label itself never required.
That only holds while a reader with standing is still on the other end. Syndication, aggregation, an audience arriving from a search result or a feed reader that's never seen the writer's other hundred posts, a scraper that doesn't care either way: none of that population has the history to catch anything. At that scale the claim reverts to exactly what it looks like on paper, four free words with nothing behind them, because the cost was never in the words. It was rented from an audience that knew you.
If "no AI used" ever becomes worth real money, a licensing deal, a marketplace that pays a premium for the human-made kind, the self-declared version stops working at exactly the moment it starts mattering, for the same reason the roadside sign stopped working once the buyer stopped being your neighbor. Somebody will build the paid version: a registrar, a cryptographic timestamp, an audit body, a fee schedule. Verification was always possible. What runs out is the room small enough for anyone in it to still be watching.
The cost was never in the word.