This amounts to the machine equivalent of "you can't beat stupid". Even once server LLMs start accounting for possible chatbot nonsense, all that'll be required

This amounts to the machine equivalent of "you can't beat stupid". Even once server LLMs start accounting for possible chatbot nonsense, all that'll be required is to move to a very cheap client LLM to generate word soup. At a certain point, it will be impossible to reliably distinguish between a dumb robot and a dumb human.