Continuity mistake: While Ethel's looking at the Baby Pictures we see her fingernails are short and not polished, but in the closeup of her hand holding one of the photos the fingernails are long with dark polish.
Continuity mistake: In season 2's episode "The Ricardos Change Apartments" their new apartment number is "3B", but in this episode when Lucy's at her audition she tells the casting agent that her apartment number is "3D" (deliberately done in order for the 3D joke to work), and it's in the next episode "The French Revue" that we see the new number "3D" on the door. (00:19:30)
Ricky's Old Girlfriend - S3-E11
Continuity mistake: When Fred tells Ricky there's an article in the newspaper about Carlota Romero, there's a closeup of the newspaper's back page with Carlota's photo, but later when Lucy takes the newspaper (the same NY Gazette issue) from Ethel, before she turns it over we can see that the back page photo and layout are different. (00:08:30 - 00:10:20)
Ricky's Old Girlfriend - S3-E11
Continuity mistake: When Fred shows Ricky the newspaper article about Carlota Romero appearing at the Opal Room, the front page of the paper reads "New York Gazette", but in the closeup of the article on the back page the newspaper is called "The Daily Record." (00:08:35)
Ricky's Old Girlfriend - S3-E11
Continuity mistake: In Lucy's dream, when Carlota Romero comes to their apartment, Little Ricky is sitting in a highchair with a hat on his head. Although later in the scene, you see his hat fall off, the first close-up shot of Little Ricky shows him without the hat. Then immediately, when you see a wide-shot of the scene, his hat is back on his head again.
The Million Dollar Idea - S3-E12
Continuity mistake: When Ethel says "He's never forgiven Ford for scooping him with the horseless carriage" Lucy is laughing. The shot changes, she is no longer laughing.
Continuity mistake: While Ricky's telling the bedtime story in Spanish to Little Ricky (worth watching just for this darling scene), in the closeups of the baby in the crib, the pillow bumper has an embroidered heart with stick figures, which flips in reverse. Actually, the last closeup of Little Ricky lying down is the normal shot, but all the closeups of the baby sitting up are the flipped shots. (This pillow bumper has stick figures of Lucille Ball and Desi Arnaz, and can be seen in previous episodes). (00:06:40)
Continuity mistake: While Lucy is at Ethel's apartment nervous about leaving the baby with Ricky she's wearing v-strap pumps, then she heads back to her apartment to get her coat and bag, but when Lucy walks into her apartment she's wearing ankle strap pumps instead. (00:16:00)
Sentimental Anniversary - S3-E15
Continuity mistake: While Lucy's showing Little Ricky the pictures in the album, we see Lucy's fingernails are not polished, but in the closeup of her hand pointing to the photo the fingernails have dark polish on them. This happens again when Lucy's looking through the album with Ricky.
Bonus Bucks - S3-E20
Continuity mistake: After Ricky takes out the extra expenses from the prize money, when starched-up Lucy walks into the office Fred's holding the last dollar bill, and in the closeup of Ethel's and Fred's shocked reactions to Lucy's appearance we see Lucy's hand holding the dollar, but in the next wideshot Lucy's open hand is empty so Fred gives her the dollar. (00:24:35)
Ricky's Hawaiian Vacation - S3-E21
Continuity mistake: When Ricky has five seconds left on Freddie Fillmore's show, in the wideshot Ricky starts singing "Let's have another piece of" and he's holding the paper with his right hand while snapping the fingers of his left, but it cuts to Ricky's closeup and the paper's now in his left hand while he's snapping the fingers of his right hand. (00:24:40)
Continuity mistake: When Martians Lucy and Ethel are sneaking up behind everyone on the Empire State Building, in the closeup Ethel has a toy gun tucked into her belt just as she climbs over the fence, but in the next wideshot her toy gun is already lying on the observation deck floor. (00:17:25)
Tennessee Ernie Visits - S3-E27
Continuity mistake: When Fred and Ethel leave to get the rollaway bed, note the two L-shape actor's marks on the carpet where Ernie had placed his small suitcase and then sat, earlier in the scene. (00:08:50)
Continuity mistake: After Fred secures the chain lock to the front door, with the chain mounted onto the frame of the door, Fred then slides the chain into the door's slide-catch to show Lucy the "burglarproof chain." When Ethel opens the door the chain itself is ripped off the frame, leaving the chain (and the piece that was screwed to the frame) dangling from the slide-catch attached to the door, but in Ethel's closeup the chain is still mounted to the door's frame. (00:01:40)
First Stop - S4-E14
Continuity mistake: When Ricky stops the car and backs up trying to locate Aunt Sally's, Lucy gets out of the car wearing a coat and a pantsuit underneath, but in the exterior shot she's wearing a skirt set when she walks over to the shed to read the sign. (00:03:50)
First Stop - S4-E14
Continuity mistake: In this episode, Fred and Ethel claim that the bed they are sleeping in is just like the one they have been sleeping on for years. It is double bed with a big sag in the middle. However in an earlier episode "Vacation from Marriage" they show Lucy and Ethel in the the Mertz's bedroom and they have twin beds.
Continuity mistake: When Ethel asks her old friend Billy to take a group photo of her with Fred and the Ricardos, Ethel poses with everyone as Billy takes only one shot of them together, but when Lucy reads the newspaper article Ethel is posed differently in the cropped "group" picture. (00:12:15 - 00:16:35)
Continuity mistake: Ethel's full name in this episode is Ethel Mae Potter; however in a earlier episode, Fred calls her Ethel Louise, and in another episode she is called Ethel Roberta.
Continuity mistake: At the start, when the Pontiac convertible turns into the driveway of what should be the Beverly Palms Hotel, the sign with the real name of the hotel can be seen, which reads Beverly Carlton Hotel.
Don Juan and the Starlets - S4-E18
Continuity mistake: After the maid sees Lucy sleeping on the couch and leaves, in the next shot the clock reads 10:00 and Lucy wakes up, but when Lucy checks the bedroom and walks back into the living room, the clock now reads 6:40. (00:16:25)
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 ★