Revealing mistake: When the cop on the motorcycle pulls Cheech and Chong over, one of the hippie girls is sitting in the front with Chong. Chong orders her to get in the back. She goes back behind the curtains and sticks her head out front. He pushes her back again. In a shot from the back of the van, you see Chong pushing her back, but you also see through the crack in the curtain that it is totally dark in front of the van. Since there is daylight outside, it shouldn't be totally dark.