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)
Chosen answer: Her agent/manager negotiated a special billing as part of her contract. It distinguishes her from the rest of the cast, probably when she became a producer on the show.
JC Fernandez