Witch Trial - S2-E1
Visible crew/equipment: While the Book of Shadows flips its pages the sisters enter the attic, and after Piper asks how the book does that, in the next shot the feet of a crewmember can be seen moving quickly out of shot, at the bottom left side of the screen. (00:03:15)
Witch Trial - S2-E1
Continuity mistake: When the book was taken, Phoebe has her necklace above her shirt, but when she runs downstairs, her necklace is underneath her shirt and then is back on top of her shirt again. (00:06:15 - 00:18:25)
Witch Trial - S2-E1
Continuity mistake: At the spiritual place Phoebe had tan marks, but later on she didn't have any tan marks. (00:10:35)
Answer: That was a mistake in the series.
Also, the episode is called 'Babies First Demon' and this alone tells us that it's Wyatt's first time in the field (so to speak) and as the sisters say, they've done a good job of clearing up their own magical messes so far. Nobody really knows how advanced Wyatt's powers are, or will become. That's why the cleaners appear, to nip things in the bud. The Cleaners didn't want to chance that the sisters could clean Wyatt's magic up, just incase they couldn't. Therefore intervening themselves, just in case.