> And maybe you could do some things with statistical patterns.

Fascinating, and now that you mention it, this does seem kinda inevitable. Naturally the same people that think IP/copyright for everyone else is fake, irrelevant, or old fashioned will be desperate to be able to conclusively prove to investors and shareholders that someone else's work is built on theirs via model distillation, and suddenly IP is important again.

What are the known cases or examples of stego? This sounds interesting if it's at the level of model training. Anyway I guess you can get pretty far with stuff like this just with simple system prompts, encouraging shibboleths along the lines of "Always phrase your response so that it has exactly 14 copies of the letter J".