Revealing mistake: When the sisters are talking in the kitchen about Phoebe crashing Prue's car, whenever Phoebe turns around you can see a distinctly grey patch of skin on her shoulder where one of the actress's tattoos is covered up.
Revealing mistake: When Phoebe punches Dr. Williamson, it's easy to tell that she doesn't really punch him.
Revealing mistake: The sheet-covered body of Charlene that is being moved by the police has obviously got a head, despite the fact that she was meant to have been decapitated.
Revealing mistake: When Maggie Murphy climbs onto the ledge of the roof to jump off you can see the surface of the ledge dipping as if it was foam.
Be Careful What You Witch For - S2-E22
Revealing mistake: During the search for the Dragon and teenage Prue, Phoebe's wearing a red top and red jacket, but when Phoebe lands on the ground we can see the bulky beige material of the stunt vest at her back, under the red top and jacket. (00:34:05)
Revealing mistake: When the pawn shop owner jumps through the glass door, it is painfully obvious that it's a stunt double.
Revealing mistake: When Phoebe opens the cupboard and the human pig falls on top of her, you can see that it's a stunt double in the far shot.
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.