Continuity mistake: While at P3, Leo tells Phoebe that she can't turn into a Harpy just by getting scratched, and when Piper cautions Leo to use discretion Piper raises her left arm to Leo, but in the next shot it's Piper's right arm that's raised. (00:16:05)
Continuity mistake: When Phoebe receives the phone call from her doctor informing her that she is pregnant, she faints and starts to fall to the right. The next shot shows her lying down as if she had fallen to the left.
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.