Sympathy for the Demon - S5-E7
Visible crew/equipment: After Paige orbs the potion onto Barbas and Cole absorbs all the powers, in the shot of Barbas getting up from the floor we can see a blue T-mark and an orange T-mark taped to the rug. (00:39:05)
Necromancing the Stone - S5-E21
Visible crew/equipment: When Piper hits the mirror after being thrown across the room by the energy bolt, look closely at the roof in the other room: a black rectangular hole with a stage light poking out of it is visible.
Visible crew/equipment: While Elise is telling everyone about Bay Mirror's new owner, Jason Dean, just as she warns them that he's known for shaking up companies, we can see the white T-mark and a bit of the yellow tape mark on the crew's black mat (which is gone in following shots) at the lower left of the screen. (00:09:15)
The Day The Magic Died - S5-E15
Visible crew/equipment: While Phoebe and Paige are in the kitchen with the unicorn they realise they've lost their powers, and when Leo joins the sisters in the kitchen we can see two animal handlers - one wearing a short sleeved white shirt behind the animal, and another holding the rope hiding under the table. (00:10:35)
The Day The Magic Died - S5-E15
Visible crew/equipment: While Paige and Phoebe are in the basement getting some magic from the unicorn horn, Phoebe figures out it was the Elders who sent the unicorn, and just as Paige comments that the unicorn's magic is not affected by what happens on Earth, you can see the animal handler's hand under the animal's muzzle. (00:37:35)
Sand Francisco Dreamin' - S5-E14
Visible crew/equipment: After Phoebe returns with a bowl of dream dust from the remains of the Sandman, Phoebe opens and closes the door to the conservatory to view their three dream guests, then as they all turn and walk toward the sofa we can see the reflection of the moving boom pole and mic in the mirror. Also, note the door that Phoebe had closed is now wide open in Leo's closeups. (00:32:15)
Visible crew/equipment: After Bacarra takes the human heart from the witch it cuts to the Halliwell manor, and as the camera pans to the right we can see lighting equipment and the boom mic (with a white striped tip) at the top of the screen, then in a following shot from the same direction the boom mic is visible again. (00:30:55)
Siren Song - S5-E4
Visible crew/equipment: While Leo is at the manor with Phoebe, who volunteered to make the potion, when Piper and Paige orb into what's left of Melissa's home, through the hole in the wall we can see the boom mic (with a white striped tip) hovering over the sisters, just as Piper tells Paige she doesn't want to make Melissa more upset. (00:24:45)
Siren Song - S5-E4
Visible crew/equipment: While Piper and Paige are talking in the kitchen they hear the news report about the fire, and when it cuts to Leo watching the news on TV we can see the red T-mark taped to the rug's red design. (00:06:35)
Visible crew/equipment: After Leo leaves Piper alone at Darryl's party in the park, when it cuts to Elise and Phoebe at P3, we can see the two T-marks on the floor behind them when they walk over to the counter. (00:12:35)
Necromancing the Stone - S5-E21
Visible crew/equipment: After Phoebe tells Jason that she'll go with him to Hong Kong in the morning, when it cuts to Piper and Paige looking out of the attic window, the reflection of a crew member is visible in the window behind the candles. (00:33:40)
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.