Wicca Envy - S1-E10
Continuity mistake: At the beginning of the episode when Piper hides her sisters from Leo she has the shirt with the buttons closed, but between that scene the shirt is not closed. (00:01:05)
Wicca Envy - S1-E10
Visible crew/equipment: After Jaime tells Prue that she's the hardest working woman he's ever met and believes she's innocent, Prue walks into the office to access Hannah's computer, and just as Prue sits down and moves closer to the desk, the blue T-mark is visible on the floor, under the office chair. (00:24:30)
Wicca Envy - S1-E10
Continuity mistake: At the end of the episode, when Leo and Piper are saying goodbye he reaches out and touches her face, but when the angle changes his hands are instantly back at his side. (00:43:05)
Wicca Envy - S1-E10
Audio problem: When talking about the tiara with a security guard Prue's mouth stops moving mid sentence but the audio continues.
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.