Magic Hour - S3-E2
Continuity mistake: In this episode, Phoebe says "Grams, you were married four times." But in "Lost and Bound," Phoebe tells Cole that Grams was married six times.
Magic Hour - S3-E2
Continuity mistake: When Piper and Prue are talking to Brooke outside, Piper's arms change from being crossed to having her hands on her hips between shots.
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.