Continuity mistake: The first night that the Gentlemen float through the college, they are on the 2nd floor one minute (all the room numbers start with 2), then they turn a corner and are suddenly outside room 118, a floor below.
Revealing mistake: When the Gentlemen are chasing Tara in Stevenson Hall, in the first hallway two Gentlemen are floating down the corridor and you can tell they're on wires because the one on the screen's left "jumps" a little as if his wires got snagged.
Continuity mistake: Near the end, when Spike takes the cup of blood from the fridge, we can see that it is full to within a 1/4 inch of the rim. However, when the shot changes and he drinks it, he tips the cup almost 45 degrees before putting his lips to the cup and drinking. If the cup had been as full as previously shown, the blood would have begun pouring out long before Spike ever drank form it.
Continuity mistake: In the season 4 episode "Doomed," during the fight at the Hellmouth, Willow throws the sack of bones to Spike, who catches them and looks startled. In the very next shot of Buffy fighting one of the demons, Spike can be seen in the upper left corner of the screen, with empty hands, quite calmly watching the fight. (00:36:35)
Visible crew/equipment: At the end when the gang leave the high school, stage lights are reflected in the broken glass of the double doors that they exit through.
Revealing mistake: In the scene where Giles and Ethan Rayne are drinking in the bar, the shots cut between Giles and Ethan frequently. When on Giles, you can see Ethan's hands/arms and his glass in the foreground of the shot, but almost every time the shot switches back to Ethan he's in a different position with no time to have moved. (00:14:40)
Visible crew/equipment: While Xander tells the gang about the "demon" he encountered, they all walk into Giles' apartment, and just as Xander heads up the stairs, the white T-mark taped to the rug is visible under the corner of the desk with the lamp, where Willow will stand. (00:27:00)
Continuity mistake: In every other episode it's seen in, room 314 is a room directly off a corridor, but in "The I In Team" Walsh walks through the door off the corridor, then there's another shot of her walking through a door. Where did the second door come from? (00:13:50)
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.
Continuity mistake: The first shot of Maggie Walsh being impaled from behind with the skewer indicates that there is no one standing close by, judging by the amount of negative space around her. However, following shots reveal that the skewer is coming straight out of Adam's wrist, therefore he should have been visible in the previous shot.
Continuity mistake: When you first see Adam lying on the bed, before he wakes up you see his human side of his face on his right side. In the next scene the camera is over Maggie Walsh's shoulder and the human side of his face is now on the left side. Then just after he stabs Maggie it switches back again.
Visible crew/equipment: When Buffy and Riley are talking at the crime scene, where he tells her about Maggie Walsh's death, one of the camera shots has a very visible black border around the entire edge of the screen as if the lens shade was visible in front of the lens and could be seen in the shot. (00:18:20 - 00:19:40)
Continuity mistake: When Buffy is talking to Riley, she puts the scarf on her head, on his hand. He talks to her and says "Maybe I am the bad guy," and in the next frame her scarf is back on her head again, then off again in the next frame. (00:24:20)
Visible crew/equipment: When Buffy, Willow and Anya are watching Looney Tunes, some stage lights are reflected in the globe behind Willow.
Visible crew/equipment: In the episode 'This Year's Girl', when the Scoobies find the demon in the woods that Adam has cut open you can see a boom mike operator in the background. (00:07:40)
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 ★