As Tina swerves off of the road after seeing her mum get killed by Jason in the middle of the road, if you look in the back of the car, you can see a camera set up, filming the shots in the back seat.
During the filming of the movie, Kane Hodder (the actor who plays Jason) was returning to his trailer one night after filming, still in his Jason costume. His trailer was approximately one mile down a dark, dirt back-road. Exhausted from filming, Kane decided to take a shortcut through the woods surrounding the area. While in the woods, he encountered a local resident, who asked Kane if he was filming the new Friday movie. Thinking it a rather foolish question, given that he was still in his Jason costume, mask and all, Kane did not answer. After the young man tried to communicate with him several more times, Kane remained staring and silent, until he lunged for the man and groaned, sending the man in an absolute panic. He was so terrified that he fell several times and struggled to his feet, screaming as he ran away. The next morning, Kane Hodder was informed that the Sheriff would be by the set later in the day for questioning, but the Sheriff never came. Definitely a hilarious, if not terrifying joke.