Continuity mistake: Huge continuity gaffe. When Anya and Xander see Spike and the robot in the graveyard it is nightime. Xander goes back to speak to Spike almost immediately and sees Glory's followers kidnapping him. He wakes goes back to Buffy's house and from there they, again almost immediately, go looking for Glory's house - and it is the broadest of broad daylight. You could see it was still night before they left through the windows of the house. It also begs the question of how they got Spike from Glory's house back to his crypt in the sunlight since they had no blanket. (00:26:20 - 00:28:50)
Continuity mistake: As Spike is escaping Glory's apartment, the doors for the elevator that he tries to get into close in front of him twice.
Continuity mistake: When Glory punches Spike into a wall at her apartment, some blood appears on Spike's lip after he hits the wall which wasn't there before when he hit the wall.
Continuity mistake: When the gang are fighting Glory's minions, one of them knocks Giles to the ground and then tries to choke him. As Giles hits the ground he lands facing downwards so we can't see his face. But when the minion is chocking him in the shot immediately afterward, he is suddenly facing upwards.
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 ★