Pros and 3rd party bindings?

Just curious and Ive never seen any one ask it. Specifically I see it at the cable whether in person or in movies and clips and what not. Why do so many riders sponsored by a company ride another brands bindings. Ive seen alot of videos of ctrl riders using ronix one bindings or specifically watson bindings. The watsons are sick, and maybe thats why they use them, but wouldnt you think a sponsor would be upset to see their riders on a different companies boots? Just curious