So lets say the final product is a 720P frame we can cut this from anyplace in the frame in RED CINE. So we take a group of background people from the
4K raw frame, assuming they are in focus, and cut a 720 of just them as the new establishing shot.
Now this is not the zoom into from full frame to a 720size which we believe is not allowed by RED Cine because "It won't keyframe"
However problems will arise when the main actor on the other side of the 4K frame walks toward camera and we tilt up. Now our nice little cut of the group in back no longer works since we can't track them.
Just my two bits worth for the value of keyframing....