Factual error: In Amends, season three, one of the movies playing at the theater is 'Abilene,' which was not released until March 13, 1999 ; three months after this episode was aired (and probably five months after it was filmed, which is interesting). (00:43:10)
Continuity mistake: During season 7 we are told several times that the First cannot take corporeal form, ie. it cannot touch things. However, in its first appearance in the season 3 episode 'Amends', when it manifests as Jenny Calender and runs its fingers through Angel's hair you can see his hair moving underneath her fingers. It wouldn't be able to do this if it weren't corporeal. (00:15:50)
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 ★