The difference is that CA skips over commercials without any user input, right?

Yup, exactly. Nine out of ten shows require no user input to watch comercial free. You start the show, every few minutes it blips and flashes a symbol on the bottom of the screen, and then after about twenty minutes you get iritated that it's missing a comerical break, pick up the remote and hit quick skip only to realize that it's the last comerical break after the show has ended. Everyone once in a while it does miss a comercial break, and every month or two of regular tv watching it has a false positive where you have to go back and turn CA off for a segment.

Matthew