Visible crew/equipment: When Willow and Dawn are running away from the demon, Willow uses magic to unlock a car for them to escape in. On the right side of the screen, shadows of crew members can be see as the car's doors open and are gone when Willow uses magic to make the car drive away.
Visible crew/equipment: Just after Dawn says "I like the trailers", we fade to black/commercials, then up again. Keep a close eye on the left side of the screen - you can see what looks like someone's hand flash into frame for a second, despite Dawn being alone in the room - looks like the director's hand signalling action. (00:25:50)
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 ★