When Jan and Marcia are riding the log ride, from their viewpoint, going down the flume, many people are visible, waiting in the line. When they get to the bottom of the drop, there are no people in line.
Mike tells Peter that part of winning the plate-breaking game is that he has to pay for it. However, at amusement parks, you pay before playing, not after.
At 20:50, during Cindy and Bobby's leg of the relay with the yellow tube, a large group of people is visible in the background watching them film the scene.