I Was Made To Love You - S5-E15
Continuity mistake: At the end of the episode when Buffy is sitting on the swing set with April, she tells April that Warren was proud of her and didn't mean to hurt her. Before she tells her this, April's hair is in front of one of the chains of her swing on the right side of her face. But after Buffy tells her, her hair is behind the chain of the swing.
I Was Made To Love You - S5-E15
Continuity mistake: At the magic shop, while Giles is talking, he is not wearing his glasses. But right after Spike leaves the magic shop, he is wearing them.
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 ★