The contract absolutely gives us the right to rent our ownership interests. It includes the word leasee in the definition of personal use.
DVC has the right to define what makes a membership a commercial one and they do have the right to make those stricter.
And if they want to ban owners from using third parties to advertise, they could try that…but would face a lot of pushback.
However, I don’t think they can decide that a specific type of rental…confirmed vs on demand…changes the nature of that rental. Meaning you could use a broker to advertise to book something but stop me because I already booked it
IMO, since what we rent are reservations and not points, I think it would hard pressed to even attempt to control how we rent.