Visible crew/equipment: When Dawn and the other girl are getting up after falling through the bathroom floor into the basement, you can see a man standing behind them towards the left side of the screen.
Visible crew/equipment: When Xander is in the bathroom after Buffy called him to look for the talisman, he bends down and grabs the talisman that lays under the sinks. As he stands the camera pans up to the mirrors and on the left side you can see the reflection of a crew member crouching over the hole to the old school. It's not the female manifest spirit as the clothes are wrong and she then appears from a different part of the room.
Visible crew/equipment: After Gnarl poisons Dawn and traps Willow inside his cave, the shadow of a camera is visible on some bushes on the left side of the screen as we see Xander and Buffy carrying Dawn home.
Visible crew/equipment: When a guy asks Dawn out to Winter Formal and she says "What?" - you can see a microphone at the top of the screen. (00:33:35)
Visible crew/equipment: During the scene where Willow and Anya fall in love with RJ after he visits Buffy's house, and everyone but Dawn runs off to do their thing, the camera pans to Dawn and a woman with a maroon, long sleeved shirt is briefly visible standing on the stairs to Dawn's right.
Storyteller - S7-E16
Visible crew/equipment: During Andrew's fantasy of him, Warren and Jonathan being Gods, something dark is reflected in of the piles of gold. Possibly a camera or camera crew.
Visible crew/equipment: When Dawn and the Potentials try to get past one of the police officers at The Bronze, Kennedy says that he'll have to shoot them all to stop them. As he responds with "It doesn't really bother me", the shadow of a boom mic can be seen on the wall behind him in the top right hand corner of the screen.
Visible crew/equipment: After Buffy has spoken with Clem and is walking down the road, you can see the reflection of a camera in the back of a green SUV.
End Of Days - S7-E21
Visible crew/equipment: Right at the end, when Angel saves Buffy from Caleb, the shadow of a boom mic can be seen in the top left corner of the screen as Angel helps Buffy to her feet and says, "I was never much for preachers."
Visible crew/equipment: When the 4 Scoobs meet in the hallway for the revolving shot, just as the camera starts to pan over you can see someone casually walk down the hall into frame behind Xander's left shoulder, as the camera starts to revolve you can the person is now crouching in the shadow behind Giles. It appears to be a crew member that accidentally walked into shot at the wrong moment and hid quickly.
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 ★