The Freshman - S4-E1
Continuity mistake: When Buffy is fighting the vampires at the end of the episode, she grabs a tennis racket and smashes the brunette vampire over the head. She falls over the back of the couch and we hear the thud of her landing, however in the wide shot of the couch the vampire has just started to go over the back.
Continuity mistake: At the end of the episode, as Spike's getting his T-shirt on, from one angle he gets his arm completely through a sleeve, then we cut to a different view and he's still pulling it on.
Visible crew/equipment: In the last scene after Buffy jumps through the window into her mother's room, Faith and Buffy begin to fight. The two wrestle into the hall and begin to roll down the stairs. There is a side view shot then a front view shot. In the front view shot you can see a camera moving downward just outside the bannister and out of shot. Only visible in widescreen versions.
Continuity mistake: When Xander falls through the ground, he lands with his arm on, or very near a bit of wood, but in a closer shot of him just before he gets up, the wood's disappeared and other rubble has moved around too.
Continuity mistake: In the scene where Buffy and Kathy are deliberately infuriating each other (tapping pencils and cracking eggs) there are several lights on throughout the room (on Buffy's desk, above Kathy's computer, in the kitchenette) yet when Buffy turns out her bedside lamp, the entire area is thrown into darkness.
The Harsh Light Of Day - S4-E3
Other mistake: We've seen before that vampires are fine as long as they aren't in direct sunlight, yet in this episode Spike is in the shade when Buffy removes the ring and he still starts fizzling.
Visible crew/equipment: At the very end of the scene where Buffy and Giles discuss what happened (including The Initiative), you can see the microphone at the top of the screen. (00:39:45)
Continuity mistake: When Buffy and Willow are talking about the sham of Thanksgiving Day at the groundbreaking ceremony, on one angle (the one where Buffy's face is shown) there is a strong wind blowing, moving their hair about, but in the other (when you can see Willow's face) their hair aren't moving.
Continuity mistake: When Adam enters the cave and is talking to the vampires and then pulls the head off of one of them, watch as he falls, his head is still visible when he is falling out of frame. (00:15:25)
Continuity mistake: When we see Veruca eating at the table, she reaches for a cup as we see Oz coming up behind her. The shot changes and we see her turning around and reaching for the same cup again, though she never had time to put it down.
The Harsh Light Of Day - S4-E3
Continuity mistake: When Buffy catches Parker talking to another girl he stands up to leave and slings his backpack over one shoulder. In the next shot it's over both shoulders. (00:34:45)
Continuity mistake: We see Xander lying in bed with his chest and stomach uncovered. But when Anya comes in and starts talking to him about checking in at the unemployment office, his bed sheets are suddenly pulled up covering his chest and stomach.
Revealing mistake: After Buffy leaves the cave where Adam kills Forrest, she trips and falls down a horizontal slope. She then rolls over some rocks and one of the rocks wobbles.
Where The Wild Things Are - S4-E18
Visible crew/equipment: After Anya has rescued Xander from drowning, they venture through the vines to the room that Buffy and Riley are in. The moment before Anya screams, "Xander, help me," a vine attacks her, but a crew member's hand can be seen (in the wide-screen version) moving the vine towards Anya.
The Harsh Light Of Day - S4-E3
Continuity mistake: When Spike and Harmony find the treasure room containing the Jewel or Ring of Amarah, after Spike stakes Harmony he removes the necklace he had on, but in the next shot he's wearing the necklace again.
Plot hole: Spike must have had his chip implanted while he was unconcious. If so, how did he attack The Initiative scientists without any pain when he tried to escape? You could argue that they programmed him to be capable of violence within The Initiative only, but why would super smart scientists program an evil being to be able to escape at the first opportunity? Joss Whedon has acknowledged this as an oversight.
Continuity mistake: After the group find out Jonathon cast a spell, Willow is holding a book to her chest. But in the side shot, the book is resting on her stomach and then back on her chest a few shots later.
Continuity mistake: When Veruca comes to Oz's cage to spend the night there, she tosses her jacket onto the round stone thingie (knob?) at the end of the stairs, and it covers the whole thing. However, when Willow discovers them in the morning and Veruca goes to pick up her jacket, you can see that it has moved. Willow didn't touch it when she entered, and both Oz and Veruca were locked up so they couldn't get anywhere near it. (00:26:35 - 00:29:20)
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 ★