It doesn't seem to be the same league of problem. Because you are going to blur the stuff in the background anyway, you can be agressive with the masking and th

It doesn't seem to be the same league of problem. Because you are going to blur the stuff in the background anyway, you can be agressive with the masking and the blurring will make it imperceptible. With blue/green screens you are making changes much more severe than just blurring (in terms of the colors, hues and shades involved). Source: Hardly an expert, but I am quite a photography geek, and I've done some work on this type of graphical algorithms in the past (not this type of fancy 3D stuff though).