Continuity mistake: Joyce is driving Buffy to school and she is wearing a pink tank top. At school that day her shirt is white, but the next day at school she is back to wearing the pink outfit. (00:15:50)
Continuity mistake: Buffy gets a massive scar on her head from fighting with Adam. This scar changes size at least twice throughout the rest of the episode.
First Date - S7-E14
Continuity mistake: When Buffy goes to save Xander from Lissa, she knocks a dagger out of her hand and it is thrown to the ground near the far end of the room. Two shots later it has moved closer to the door.
Once More, With Feeling - S6-E7
Continuity mistake: When Buffy jumps off the stage in the Bronze that Dawn and Sweet are on and starts dancing, one of Sweet's goons that is lying unconscious moves from the far left of the bottom of the stage to the far right between shots.
All The Way - S6-E6
Visible crew/equipment: A boom mic is reflected in the window of Buffy's house when she and Xander sit outside discussing his engagement to Anya.
Continuity mistake: After Buffy decides not to take the antidote to the demon's venom, we cut to a scene at the mental institution. She says she wants to go home with her mum and dad. As she says this her dad puts his hand on Joyce's left arm. In the following shot, Joyce suddenly has her right hand on top of his when it wasn't in the previous shot.
Continuity mistake: When Oz leaves and holds Willow close to him, the position of their noses changes depending on the camera angle. In the shots of OZ they're pressed together and in the shots of Willow they're not.
Audio problem: The drummer in Oz's band's movements don't match the song that is heard when we first see them performing at Buffy's house.
Continuity mistake: When Buffy decides to leave again and goes to her room to pack, her door is three quarters shut when she goes in, half open when Willow comes in and almost fully open when Joyce comes in. At no point does anybody touch this door.
Continuity mistake: Towards the end of the episode when Buffy is running along the rooftops trying to catch up to the school bus, we see an overhead shot of one of the buildings collapsing just before she jumps off it. In this shot, Buffy is not holding the scythe that she used to kill Caleb. Once she jumps the rooftop however, she is holding it in her right hand.
Continuity mistake: During Anya's pep talk to the Potentials, Andrew draws crude illustrations to visualize what she is saying. One the second page that uses to draw a picture of the sun, the top of the previous page that's folded over the back of the board changes from being folded straight to folded at an angle between shots.
Continuity mistake: When Buffy is discussing the Turok-Han with the potential Slayers in her dining room, one of them says that it almost killed Buffy. Rona then spreads both her arms out and says, "What chance do we have?" In the following shot, her left arm is down by her side and her right arm is resting on the dining room table.
Revealing mistake: When Spike is playing with the Buffybot in his crypt and has her throw him onto his bed to stake him, the shot of him landing on the bed and the Buffybot climbing on top him is portrayed by stunt doubles. The shot is then interwoven with another shot of the actual actors. But it's very obvious due to the poor editing.
Continuity mistake: In the scene where Willow and Tara are at the old High School looking for Riley, Willow uses magic to light up the hallway. Tara then asks Willow how she did it. As Willow tells her that she taught her, she tucks her hair behind her right ear. Then after Tara says, "I taught you teeny Tinker Bell light", Willow's hair is hanging back down over her right ear.
Where The Wild Things Are - S4-E18
Visible crew/equipment: While the house is becoming "Wild", Riley takes Graham down to The Initiative. Once the door closes behind them and the mirror returns to its original position, the shadow of a camera is reflected in the mirror. It's in the middle of the frame, on the left, over a book case.
Visible crew/equipment: In the scene at Buffy's house, her mum comes into her room and says "Buffy, I'm home". As she says this a boom mic is visible above her head.
Chosen answer: From what we see in the series, certain girls are identifiable as potential Slayers - Kendra clearly fell into this category. The identification method is presumably mystical in nature, but the Watchers' Council are pretty effective at that sort of thing, so they're quite good at tracking down the potentials ahead of time. Not perfect, though - it does appear that Buffy herself may have slipped through the net - certainly she had no inkling of what she was until she'd already taken on the role of Slayer. It is possible, however, that this was actually cultural - an American family would hardly be likely to turn over their daughter to some strange man for 'training', so the Watchers might have chosen to keep an eye on her covertly, whereas some other cultures (like Kendra's Jamaican parents) might be more willing to believe.
Tailkinker ★