Power Outage - S3-E7
Revealing mistake: When Astral Prue kicks Leo/Balthazar in the face during the training drill near the start of the episode, her foot misses his face yet he still reacts as if hit.
Power Outage - S3-E7
Revealing mistake: Alyssa's tattoo is visible when Phoebe leaves Cole's apartment after she fought with her sisters.
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.