Confidence and Paranoia - S1-E5
Visible crew/equipment: When Rimmer says there was nothing wrong with his casual clothes, a boom mic shadow can be seen moving at the top of the screen. (00:06:10)
Confidence and Paranoia - S1-E5
Visible crew/equipment: In the medi-bay, when Rimmer says, "How about an anal reading?" a yellow microphone appears above his head. (You can see this if you watch the dvd on your pc, as some tv's can cut off the edge of the picture). (00:11:00)
Confidence and Paranoia - S1-E5
Visible crew/equipment: When the skutters try to move Lister in the Medi-bay, you can see the cable which pulls Lister's chair in the bottom right of the screen. (00:12:40)
Answer: The cello is a large four-stringed instrument, which, when it is played, stands vertically on the floor between the player's legs (assuming they are seated). If it is to grow as large as the other instuments mentioned will, it would require a rather unseemly lack of femininity to be able to encompass it with the legs.
Rooster of Doom