Visible crew/equipment: While Lucy starts taking notes about Ethel, Fred walks in and soon asks, "What's going on this booby hatch," then just as Lucy rushes back to the desk, we can see the end of the set wall and there's some kind of partition in front of the kitchen set. (00:02:35)
Visible crew/equipment: When Lucy tells Ricky, Fred, and Ethel that she made a carbon copy of the novel they just burned in the fireplace, the actors' tape marks are visible on the carpet when Lucy says, "Pardon me," in the wideshot. Then later, when Ricky, Fred, and Ethel walk in while Lucy's typing up her sequel, they stand at tape marks again. (00:11:05)
Character mistake: When Fred, Ethel, and Ricky confront Lucy on what she wrote about them in her novel Ricky states "I'm so hammy I should go lie down between two slices of rye bread." This is incorrect. Lucy wrote "He turned into such a big ham you could stuff him with cloves."
Answer: There is no reason. It's a just a silly plot device, typical of the era. Women characters were often portrayed as making uninformed assumptions or decisions.
raywest ★