I imagine it's already happening, but not at price points most of us would ever afford.
I.e. I'm not really going to pay lots of money to, say, 1) find a doctor that does not use AI as part of their work, and 2) legally/contractually enforce this is the case. However, I can imagine a government agency or a large company contracting out to some think tank or research organization, and paying through the nose to get a legally binding guarantee that no AI will be used as part of that work.
