I noticed on the Blade Runner CAV discs that one of the side changes was in the middle of a scene, when the side flips are removed and the colour balance adjusted so the two halves of the scene match, the picture goes more grainy at the join when the video is first being read from the outer edge and then the inner edge. But watching the DVD I made it's only noticable if you know to look for it and in what scene.

One of my laserdiscs (Deep Red, 1994) the first side is CLV and the 2nd is CAV, sometime I'll capture it in and see if there's any noticable picture quality difference between the sides. Another laserdisc I have only has one side, the other is just white plastic, looks kinda weird.