Visible crew/equipment: In London's suite, when Arwin opens the door to the porch where the hawk is nesting, the reflection of a crewmember wearing a white shirt is visible on the door's glass panes.
Visible crew/equipment: When Cody and Zack walk into London's suite and find Moseby there, crewmembers are reflected on the glass door behind Cody. First in the wideshot, when Moseby explains the plan to capture the bird and then in Cody's close-up.
Nurse Zack - S2-E29
Visible crew/equipment: After Patrick dumps the cake on Moseby, he wipes some away from his eyes. At the start of the next shot, when a crewmember's finger moves across the bottom of the screen it cues Patrick, who makes eye contact with the finger, to exclaim his line, "You did this on purpose!"
Answer: Keep in mind, Muriel wasn't very popular. So the writers/directors must have thought it'd be a good idea to let go of the character. No one seems to be complaining.