I was there and I noticed the camera ops were using 2D screens to frame and focus the shots. Personally, when I shoot 3D for more than a couple minutes, I switch the cam monitor to 2D as well because (for me) shooting 3D video wears my eyes into fatigue 10 times faster than just watching a movie. I don't know if it's the glasses free screen or the fact I am working constantly to adjust the exposure, focus, and with 3D I'm making adjustments to the convergence which is really taxing on the eyes. After awhile, I have to let go of the convergence task and concentrate just on focus and exposure, which is just a 2D job. Worry about convergence in post!