Deliberate mistake: When the investigators are in the basement wine cellar, they turn on their flashlights to illuminate the pitch black area as they walk around. However there is a light source moving with the camera shining on them as they are casting a shadow behind them.
Deliberate mistake: Nina first wrote 'Born to Try', the song which was being released by Delta Goodrem (the actress that plays her), along with the show. She then managed to just 'inprovise' the tune and words to her (Delta's) third single 'Innocent Eyes'. I'm sure now Nina is a popstar there will be many more to come.
Deliberate mistake: Here, as in many other episodes, Doug and Tony are time-shifted wearing period (in this case, Viking) clothing. But they tumble into their next adventure magically wearing their left-behind 20th Century clothes again. (00:45:30)
Suggested correction: A comment, not a correction to your astute and correct observation about the Time Tunnel. Aside from it being episodic television that allows characters to look the same in all situations, I believe Tony and Doug keep their clothing, hair length, lack of facial hair, etc, because the Time Tunnel "remembered" the exact disposition of Tony and Doug when they first entered the Tunnel, allowing them to keep their clothing, hair length, etc., as they slip through time. Any "Time Tunnel" aficionados wishing to add more to this would make a fascinating discussion.
A valid speculation with which I agree, but as the poster himself points out, not a correction.
Deliberate mistake: When a patient who is given CPR is seen in the shot, the person giving the CPR does so with bent arms (the correct way to do it is with straight arms). This is deliberate, as straight-arm CPR puts in an amount of strength that frequently breaks ribs. Many films do CPR with bent arms rather than straight to avoid harming the actor.
Deliberate mistake: For reasons unknown and unexplainable, the otherwise spacious and well-equipped Moonbase has halls and doorways too short for the average human to fit through without ducking. (00:20:00)
Deliberate mistake: In the scene where the ministers are all crammed into the train carriage if you look over Jim's shoulder there is a sign ("Notice" "In case of Fire" etc), while the headers are in English the actually paragraphs are written in gibberish.
Deliberate mistake: Beth shoots Bryce three times in the chest, and he falls face down on the floor. She then drags his body across the floor, also face down, to in front of the sliding door, but there is no sign of blood anywhere.
Suggested correction: In the early Seventies, no television show used blood effects. They were too expensive and would severely restrict potential audiences as television channels were notoriously conservative in those days. This is a creative and technical decision, not a mistake.
Pipe Dreams - S3-E11
Deliberate mistake: When Zack brings an oil covered Becky to the biology teacher, you can see that it's a fake duck.
The Ghost Next Door (1) - S4-E3
Deliberate mistake: Right before rising to check out who was calling her name, Hannah sets her laptop, which she was using to write a letter, on the bedspread. The computer screen is shown to be blank, meaning, 1. she switched it off, which she didn't, or 2. it was out of order, which doesn't make sense since she was using it seconds before. (00:02:10)
Deliberate mistake: Very often, during Skype or other video chat conversations, the people on the computer screen look left or right when talking to someone who is not directly in front of the screen. Although it certainly helps the viewers understand who's talking to whom (which is why I assume it's a 'deliberate mistake'), it isn't realistic, since it implies that the people on the screen are actually constantly looking away from their computer instead of at their screen or webcam.
Deliberate mistake: On several occasions throughout both series/seasons, whenever a Terminator fires a weapon, they blink. This should not happen because that would be a human reaction - Terminators aren't human. They're made to look and act human, but SkyNet don't focus on the little things; such as emotions, breathing and reflexes. The three most notable instances of this are in Season 1, Episode 5: "Queen's Gambit", Season 2, Episode 21: "Adam Raised a Cain" and Season 2, Episode 22: "Born to Run". In "Queen's Gambit", Cameron blinks as she fires a machine gun at the T-888 in the back of the black van as he runs towards her, in "Adam Raised a Cain" the water delivery Terminator blinks as he shoots Savannah Weaver's nanny Debbie and as he shoots the security guard and Catherine Weaver in "Born to Run".
Deliberate mistake: Whenever a punch is thrown in this series, the punch either stops before it hits the person or goes beside them. It's most obvious in the last episode when General Melchett says 'Excellent native cockney wit' and punches Baldrick.
Deliberate mistake: The first 10 episodes of Season 5 were shot in a totally different order than they were aired. As a result, Jamie's size during her pregnancy is very inconsistent at the beginning of the season. In particular, she gets much smaller between episode 8 and episode 9 because episode 9 was originally supposed to air earlier in the season.
Deliberate mistake: When Wonder Woman is bouncing around in the padded room, there's one part where you can tell the stunt double is not Wonder Woman.
Deliberate mistake: As the Wraith "stun bomb" activates at the SGC and everyone falls to the ground, it is visible how everyone uses their arms to dampen the fall.
Deliberate mistake: Rob is about to leave his room, and he opens the bedroom door to the noise of a loud music box that was originally being made by Laura's music box that holds jewellery in it.
Deliberate mistake: 9/6/10: When Lucas and Jade are getting into the car, look at the road sign behind them. Lucas is driving down a one way street the wrong way. Also the camera light is reflected in the side of the car.
You Wish ('Shanghaied') / Gary Takes A Bath - S2-E11
Deliberate mistake: Spongebob gets stuck in the top of a tree as Gary removes the ladder. In previous episodes it's quite clear that he's more than willing to 'fall' as he takes no damage when hitting the ground due to the low fall speed.