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)
Other mistake: When Ricky puts the baby in the crib and begins telling him the bedtime story, in the closeups Little Ricky's sitting up beside the crib rails (at Ricky's side of the room), but in all the wideshots when the camera pulls back to show Ricky's lively storytelling, we can see that Little Ricky is not where he should be.
Continuity mistake: While Ricky's telling the bedtime story in Spanish to Little Ricky (worth watching just for this 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)
Visible crew/equipment: When Lucy, Ethel, Ricky, and Fred are in the living room having coffee, the actors' tape marks are visible on the carpet around the coffee table.
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 ★