Visible crew/equipment: Just after Paige casts the spell to rid Piper and Leo of the gods inside them, the tip of the boom mike is just in shot above Paige's head. (00:33:10)
Charrrmed! - S7-E4
Visible crew/equipment: When Sheridan gets off the phone and tells Agent Brody that he checks out for now, in the next shot as Brody walks toward Sheridan we can see the T-mark on the floor where he had been standing. (00:24:40)
Visible crew/equipment: After Phoebe fails to convince herself to push the elevator button she bumps into Les anyway, and when Phoebe tells him she's a "busy little bee" the camera angle changes, and we can see the pink and white T-marks on the floor. (00:10:00)
Visible crew/equipment: After Leslie decides not to ring the manor's doorbell he turns around, and when he sees Phoebe as she walks up the steps, the reflection of crew members is visible on the car window behind Phoebe. Then as Phoebe and Les are talking, we also see the reflection of the boom mic on the window of the car in the driveway. (00:40:15)
Someone to Witch Over Me - S7-E7
Visible crew/equipment: When Kyle orders the helicopter to keep recording the survivor from the fire, Paige tells Phoebe that Kyle is really cool, then as Phoebe and Paige follow Kyle they pass the Celerity demon, and we can see the red T-mark at the demon's feet. (00:02:05)
Someone to Witch Over Me - S7-E7
Visible crew/equipment: After Paige's guardian angel is snatched by Sarpedon, when Phoebe rushes out of the kitchen to find Paige lying on the floor, two long white tape marks are visible on the floor to Paige's left and right. (00:16:15)
Visible crew/equipment: While Leo and Piper are at the photography studio with their kids the Avatars appear, and in the shots facing the Avatars the red tape mark is visible on the floor, in front of Avatar Alpha. (00:01:10)
Something Wicca This Way Goes - S7-E22
Visible crew/equipment: When Agent Keyes enters the manor and walks into the kitchen, just as the hazmat team tells Keyes it's OK to breathe the air, the red tape mark is visible on the floor in front of Keyes' feet. (00:37:00)
Visible crew/equipment: While Billie is in the dorm room with her friend, Taylor, talking about the disappearances, when Taylor gets up and stands beside Billie, the pink tape mark (it's a toe box mark) is visible on Billie's seat. (00:07:20)
Visible crew/equipment: When the smoke alarm starts blaring at the manor JD freaks out, and as he runs out of the door the reflection of a crew member wearing shorts is visible on the glass door. (00:23:05)
Visible crew/equipment: At the bank, when Nick gets off the phone after talking to his son he walks around the stanchion, and as he says, "I never wanted to hurt anybody," we can see the light green T-mark on the floor where he had been standing. (00:29:15)
Visible crew/equipment: After orbing into the manor's attic Paige reveals to Rohtul that she switched identities with Billie, then when the real Billie walks out and joins the sisters, we can see the pink T-mark at the bottom of the screen. (00:39:35)
Visible crew/equipment: When Piper is coming down the stairs with the staff, if you look in the top left corner of the stairs, you can see a piece of camera equipment moving.
The Last Temptation of Christy - S8-E15
Visible crew/equipment: At the start, Piper tells Billie she needs to be patient with Christie, and when Piper adds that if Billie needs anything they are just a call or an orb away, the pink tape mark is visible on the floor at Billie's feet. (00:01:10)
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.