Revealing mistake: When Phoebe goes to sign her papers at the end, she spells her name as Pheobe. (01:22:45)
Revealing mistake: When Piper blows up the painting you can see the hole used to put the charge into to blow it up. (00:57:40)
Continuity mistake: When Paige goes to Cole for help saving Phoebe, she puts her hand on his chest. In the next shot, her hand disappears, with no time for her to have moved it. (01:11:35)
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.