A Paige from the Past - S4-E10
Other mistake: When Piper and Leo are talking to Phoebe about Phoebe's fear of accepting Cole's marriage proposal, Piper comments "...even though he could rip your throat out with his teeth", but the closed captions mistakenly read "with is teeth." (00:05:05)
A Paige from the Past - S4-E10
Factual error: On the wall of Paige's bedroom when she was a teenager is a Metallica poster for "Garage Inc.", a CD not released until 1998 although Piper later says that Paige has gone back to 1994. (00:16:05)
A Paige from the Past - S4-E10
Factual error: When we see Paige's 1994 bedroom, she has what appears to be a Bride of Chucky doll. The movie "Bride of Chucky" wasn't released until 1998. (00:16:20)
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.