Visible crew/equipment: In the scene when Miyagi and Daniel are about to get into Miyagi's truck and drive to the Cobra Kai Dojo, Daniel is yawning and to the bottom right of him the boom mike can be seen for a few seconds.
The Karate Kid (1984)
1 visible crew/equipment mistake
Directed by: John G. Avildsen
Starring: Elisabeth Shue, Ralph Macchio, Pat Morita, Martin Kove
Revealing mistake: When Daniel is running from Johnny and his gang after the bathroom incident at the dance, there's a lot of fog outside. If you look at one of the trees in the background, you can see that all the fog is being puffed out from behind the tree - obviously a fog machine.
More questions & answers from The Karate Kid
Answer: Daniel's wounds came from fighting the Cobra Kai guys but he tells Miyagi that he was injured falling off of his bike. Miyagi sees through this and sarcastically says that he's lucky his hand wasn't hurt.
Damian Torres
I think he was also subtle letting him know he knew he didn't really fall off his bike because if he had, he would have at the very least scraped his hands...especially if he fell hard enough to cause that much damage to his face.
He was still trying to hide it. However, if you fall, you instinctively put out your hands, and they would be scraped up. Miyagi, older and experienced in life, knew better, but Daniel wasn't going to admit it outright.