Ads in the results I guess? Ask ChatGPT to write you an essay and it has a couple of paragraphs of how great Coca-Cola tastes.
In fairness, once the investors start putting pressure of monetization on these AI chatbots, and ads and product placement starts to creep in AI generated content[1], that would make it easier by people, teachers and evaluators, to detect it, brought to you by Carl's Jr.[2].