> It's very possible that they never will, that instead the advertising will be so subtle nobody will be able to detect it.
I was going to write a rebuttal to this, about how more subtle forms of advertising are likely not very effective, and then I remembered subliminal advertising.
It's largely been banned (I think), but probably only because it's relatively easy to define and very easy to identify. In the case of LLMs, defining what they shouldn't be allowed to do "subliminally" will be a lot harder, and identifying it could be all but impossible without inside knowledge.