One outstanding example of it would be during the pod race in Star Wars - Phantom Menace. From the looks of it, Anakin’s pod is pulled by turbine (jet) engines and yet for the most part of race, the sound is that of an internal combustion engine recorded from auto race track (DVD disc #2 explains it). Even though this is a science fiction / fantasy, that portion was too far-fetched.

Now this opens up a whole new can of worms. In Star Wars and other movies containing scenes in the space, you hear the sound of explosion, propulsion engine whizzing by and … etc. How could that be? The space is a vacuum. There’s no air to transfer vibration (sound). In the movie 2001 Space Odyssey, they made it true to the reality when they show space scene. The public’s reaction was somewhat less than what the movie maker wanted based on what I’ve heard. When movies and TV shows started to add sound even if the activity supposedly takes place out in the space, people got excited (or entertained) more. Why is this the case one may ask? Like I’ve mentioned already, it is an entertainment. I’ve also mentioned earlier in this thread that if the movie is based on actual event like Black Hawk Down or U571, the sound should be closer to reality which would fit better with the rest of the movie, IMO. I believe the general public is sophisticated enough to know where to draw a line. If they see something so far-fetched in a fictional movie, they may laugh or roll their eyes like I did to the sound of Anakin’s pod engine. On the other hand, if a school teacher starts to feed far-fetched information to kids, that would be much more perilous.