C3PX said:
The stupid thing was that they pretend it was a real hologram. "We have Jessica live via hologram" "You're a hologram now" "How do you feel being the first one beamed in" (oh yeah, good Star Wars terminology right there) "I'm following the tradition of princess Leia!" They made a big deal about it, which just highlights how lame it was that it was fake. If they had simply just done it without saying anything and not calling it a hologram, it would not have been as insulting to our intelligence.

They did lie outright although it is a bit different than simple bluescreening because it is a live conversation and the did have like 30 cameras pointed at her. I believe its called a "tomogram" when a 3d image is composited in a scene live. They could change camera angles and whatnot and she would still be in the right place.