Continuity mistake: In many historical flashbacks, most notably Spike's and Anya's, hair and wigs differ greatly from previous flashbacks or episodes. The director even discusses it during the commentary on Lies My Parents Told Me, saying that he doesn't understand why the wigs aren't consistent.
Beneath You - S7-E2
Continuity mistake: Shortly after the opening credits we see Buffy, Dawn and Xander driving to the new high school. As they're talking, the rest of the credits roll by onscreen. Just after "Producer: Marc David Alpert" is shown, there is a side-angle shot of the car and you can see Xander's left arm resting outside on the open door window. But in the following shot he has both his hands on the steering wheel.
Continuity mistake: In episode 'Same Place, Same Time', Gnarl cuts Dawn across the stomach paralysing her and ripping her shirt, but when Buffy and Xander are carying her home there is no tear in her shirt or any blood. Also when Buffy goes back to kill Gnarl he tears her shirt but seconds later the rip has gone.
Continuity mistake: In the final scene with Buffy and Willow at the end of the episode, the position of Buffy's right bra strap keeps changing throughout the entire scene.
Continuity mistake: When Cassie and Dawn were talking, just before Cassie got kidnapped, Cassie put her hand on Dawn's shoulder, but in the next shot, her hands were by her side.
Continuity mistake: Towards the end, when Buffy stops the arrow, when she first grabs it her hand drops down to Cassie's mouth level, and her arm's bent at the elbow. When we cut to another angle it's now held at arm's length and at about eye level.
Continuity mistake: In the flashback to St. Petersburg, 1905, just after the burning man runs out of the room, Halfrek mentions the Revolution. Between shots, Anya's champagne glass switches from her left hand to on the table and back.
Continuity mistake: When Dawn is in Principal Woods' office to talk about the accident, she gets up and leaves. Her bag is still hanging from the chair, but she has it in the next scene.
Continuity mistake: When Anya is sneaking into Spikes room after she closes the door the shot goes to spike and the sheet is lying square across his stomach and the camera goes back to Anya she then walks over to the chest of drawers and we see spike in the shot and the sheet is now lying at an angle so we can see his hip.
Continuity mistake: When Willow confronts Andrew outside the butcher shop, her hair changes position between shots throughout the entire scene.
Continuity mistake: When Buffy ties Spike to a chair before the opening credits, she ties a rope around his left arm three times. But two extremely fast shots later, the rope is tied around his left arm four times.
Continuity mistake: Before the gang head over to the high school basement at the beginning of the episode, Dawn's hair is straight with curly ends. But once they're in the basement her hair is suddenly curled all over.
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.
Continuity mistake: Towards the end of the episode, during Buffy's fight with the Turok-Han, at the construction location, her shoes are very obviously some sort of practical flat shoe, but during her speech afterwards, she is wearing fashion boots with heels.
Continuity mistake: Spike tells Buffy about drugs The Initiative would give him when his chip started firing after he was first captured. This is wrong in two ways: firstly, we saw most of Spike's time in captivity, and he escaped before they could drug him, and secondly, he didn't even know he had a chip until he escaped and tried to kill Willow.
Continuity mistake: When Willow is out with Kennedy, Willow tells her that she doesn't get why she likes her. As she says "I still don't get it", she pulls her hair back over her left ear. Then when she says "Why you like me" in the following shot, her hair is hanging back down over her left ear again.
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.
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 ★