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 the ubervamp is at the door of the Summers' home, you can see a black string attached to the inside of the door.
Other mistake: When The First (disguised as Eve) tells the Turok-Han to kill everybody except Buffy, it runs past her towards the exit of the crypt. The First then says, "Well, alone again", turns to face Spike and transforms into Buffy. In this shot, the Turok-Han can be seen still leaving the crypt, even though it had plenty of time to reach the exit and was running towards it at full speed.
Audio problem: When Giles and Anya are talking to the demon, trying to get him to open the portal to Beljoxa's Eye, when you see Anya's face from the side, her lips don't sync up with what she is saying, and sometimes her lips are moving to words when she doesn't have any lines at all.
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.
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 ★