Visible crew/equipment: When Phoebe and Paige are trapped against the wall/stairs by the web, the seat that Paige rests on is visible, together with supports under her feet - also note the decorative stair baluster has been removed.
Crimes and Witch-Demeanors - S6-E19
Visible crew/equipment: After the opening credits, in the first shot Phoebe is at the stove, then when she turns to walk toward the Book of Shadows we can see the pink T-mark taped to the crew's black mat at the bottom of the screen, which will be where Chris stands shortly. (00:03:25)
The Legend of Sleepy Halliwell - S6-E14
Visible crew/equipment: When Leo and the sisters enter the great hall we hear Gideon call to Leo and thank him for coming, then as the camera pans to the left we can see the T-mark on the floor, at the bottom left corner of the screen. (00:09:25)
Valhalley of the Dolls (1) - S6-E1
Visible crew/equipment: When Chris tells Phoebe that Paige erased Piper's memory, Phoebe shouts Paige's name then walks away from Piper, and in the next shot we can see two pink T-marks taped to the floor under the table, where Paige is holding Wyatt. (00:27:05)
Visible crew/equipment: In the scene with Chris and David in the attic, a boom mic dips into the shot. (00:28:50)
Witch Wars - S6-E21
Visible crew/equipment: While the demons are watching Witch Wars at the bar, when the show's host, Corr, is holding an athame he tells viewers the winner will be awarded a serious power boost, then just as Corr says, "Since the shapeshifter..," in the shot of the demon bar patrons, we see the T-mark (it is not part of the Witch Wars show) taped to the floor under the table. That T-mark is visible again in at least three following shots. (00:23:35)
Crimes and Witch-Demeanors - S6-E19
Visible crew/equipment: After The Tribunal reverse the decision about Darryl he reappears at his desk and he hugs Sheila, then as the camera pans around to reveal The Cleaner standing in the doorway, we can see the white tape mark on the floor behind his feet. (00:39:00)
Answer: "Hush, Hush, Hush" Paula Cole.