Continuity mistake: When Bruno is talking to Kunal Nayyer at the beginning of the movie, Bruno asks him to talk into the camera. Kunal's hair changes from being long in the back to suddenly cut short. The most obvious part is when Kunal says "No, I don't think so". When the camera cuts to Kunal saying his line, his hair is back to being long again. (00:02:10)
Continuity mistake: In the diner scene where Bruno commits "carbicide" the exterior light goes from night to day then back to night.
Continuity mistake: In the scene where Bruno first meets his new agent, there is a cowboy hat on a hook on the office door behind Bruno. The hat changes position, 1st to a full view of the top of the hat, then in the next shot the hat is sideways on the hook. In the next scene the hat is back to its original position.
Answer: This is not a hidden camera movie. Everyone filmed believes they are being filmed for a documentary. So the swingers knew they were going to be filmed, but didn't know the shenanigans SBC was going to pull. The camper dude probably started realizing there was something weird going on and got mad that he was being made fun of, so knocked over the camera.