Continuity mistake: When Faith is waking past the movie theater, the same couple passes behind her in 3 identical shots. (00:19:29)
Continuity mistake: In 'This Year's Girl' when Faith is taunting Joyce with all Buffy's uncollected mail she flings the envelopes across the bed one by one, scattering them. When Faith is fighting Buffy later on they are all in a pile again. (00:37:20 - 00:38:40)
Continuity mistake: When Buffy and Riley are in Buffy's room, Buffy holds Riley's hand with both of her hands and says to him, "Is there anything I can do?" But in the following shot she is holding Riley's hand with only one of her hands.
Continuity mistake: In the scene near the end when Faith is putting Joyce's lipstick on in the mirror and taunting her, it is obvious that the make-up department forgot to put Faith's tattoo on her upper arm. It's obvious if you watch back and forth between the mirror and the shot of Faith standing and turning, there is no evidence of a tattoo that has been established Faith has in the previous season.
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.
Revealing mistake: When Faith is being chased by Buffy she jumps over a brick wall but as she does the wall wobbles.
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)
Visible crew/equipment: When Giles, Willow, Tara and Buffy (in Faith's body) arrive at the church in the armoured van, a camera is reflected in the van's back window.
Revealing mistake: When Jonathan assists Buffy at the beginning of the episode, he enters through the glass ceiling of the mausoleum, which shatters into squares. Although the audio is the sound of glass shattering, the pieces of "glass" flutter down, revealing that the squares are paper - simply for the safety of the actor during the stunt. (00:05:00)
Visible crew/equipment: After Tara is found in the Janitor's closet and brought back to her room as Willow & Buffy come in, there is a mirror to the left of the door. It has a scarf draped over it to prevent it from reflecting things it shouldn't, but the bottom right corner is still exposed and in it you can see glimpses of the crew moving around behind the camera.
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.
Revealing mistake: When Tara is being chased by the monster and she falls, she says a spell and white smoke comes out of her hands but it is coming out of the sleeves of her shirt, the way she holds her hands up suggests this as well.
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.
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.
Where The Wild Things Are - S4-E18
Visible crew/equipment: When Xander and Anya pull over in the ice-cream van, the front windscreen is very reflective. To avoid reflecting the camera crew, a giant screen was put in front of the ice-cream van - which, ironically, is reflected in the windscreen. It isn't a reflection of another vehicle parked in front of them as the thing that is reflected is a curved shape.
Where The Wild Things Are - S4-E18
Visible crew/equipment: In the scene where Xander and Anya make the last attempt to rescue Buffy and Riley, Anya is attacked by some vines and you can see another set of hands from the crew pushing the vine towards her.
Where The Wild Things Are - S4-E18
Visible crew/equipment: Toward the end of the episode Giles, Tara and Willow contact the spirits. Just after the spirits vanish, in the bottom left corner of the screen a crew member's leg is visible.
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 ★