The Return - S1-E19
Continuity mistake: When Mr. Gold is talking to Dr. Hopper in his office, there's a box of tissues on the table. The amount of tissue paper sticking up from the box keeps changing between camera angles. (00:26:15)
Continuity mistake: When Emma and August are walking down the streets of Storybrooke in the morning, in the first shot, they are walking past Storybrooke Dental. Cuts to another shot, and they are now walking next to the Clock Tower building. As the shot ends, they are walking past a window covered in newspapers. In the next shot, they walk past the very same window again. Cuts to another shot, and they have suddenly walked past the building as they are crossing the street. (00:01:20)
Continuity mistake: When Emma and August are walking down the street in the morning, as he says "Take the day off. Come with me, and I'll show you", behind them, a man and a woman can be seen crossing the street. In the next shot, the exact same couple crosses the street again. (00:01:50)
Continuity mistake: When Mary Margaret is talking to Regina in the school yard, her fringe keeps changing between shots. (00:08:00)
Continuity mistake: In Pinocchio's home, when Jiminy Cricket pops out of the cuckoo clock, a navy officer doll can be seen sitting on a table as Geppetto goes to release the cricket. In the first shot, the doll is perpendicular to the chair next to the table, but when Jiminy says, "It's okay. He meant no harm", the doll has turned around 90° and is parallel to the chair. After the Blue Fairy shows up, the doll is back to its original position. (00:12:30)
Continuity mistake: When David is carrying Regina's groceries, there's a plastic bread bag sticking out of one of the grocery bags. The amount of plastic sticking up repeatedly changes between shots. (00:15:45)
Continuity mistake: When David is having dinner with Regina, as Regina says "How did you like it?" her left hand is lying on the table. In the next shot, her hand is under her chin. (00:20:55)
Continuity mistake: When Pinocchio takes baby Emma in his arms, in the first shot, her baby blanket is wrapped tight around her. In the next shot, it is wrapped in a completely different way, less tight, with huge folds and the purple bands are tied up differently. In the next shot, the blanket is tightly wrapped around her again. In addition, when Pinocchio finds Emma inside the tree trunk, the way the blanket is wrapped around the baby is different from the way it was when Charming sent her through the magical wardrobe in "Pilot." (00:29:50)
Continuity mistake: There's a flashback to the life of young Pinocchio, played by brown-eyed Jakob Davies. But adult Pinocchio, Eion Bailey, has striking bright-blue eyes. It's possible that a blue-eyed child may grow up to have brown eyes, but the opposite does not happen.
An Apple Red as Blood - S1-E21
Continuity mistake: In Regina's dream, when she walks away from the dinner table to answer the doorbell, she is wearing black pants. When she is tied to the tree, her pants are grey. (00:01:05)
An Apple Red as Blood - S1-E21
Continuity mistake: When Regina offers Jefferson a drink, he declines by dropping the white rabbit card in the glass. In the next shot, the card is gone. (00:12:55)
Continuity mistake: When Emma finds Snow White's glass coffin, there's a hole in the lid. In the overhead shot, the hole is rather small, but in the shot from inside the coffin, the size of the hole has changed dramatically. In the next shot, it is small again. (00:20:15)
Continuity mistake: In "That Still Small Voice", when Regina throws the piece of glass down the shaft, it lands on the rest of Snow White's glass coffin, which has several holes in it. When Emma finds the coffin in this episode, there is only a single hole in the glass, and the ends of the coffin (made of wood), are much smaller. (00:20:15)
Answer: He knows who she is because he knows that the fairy tales are true. He was also shown to sneak out to go see Emma or someone else. Sometimes he succeeded, sometimes he didn't. This is how he knew to look for her despite his strict mother.