Visible crew/equipment: When the chicks are running loose in the living room, and Lucy, Little Ricky, Fred and Ethel are trying to corral them, you can see the chicken wire and braces set up to keep the chickens on the set. (00:20:20)
Other mistake: In the first scene when Ricky staggers down the stairs and on his way to work it's supposedly first thing in the morning but the hands on the Grandfather clock are at 12 Noon/Midnight. (00:00:45)
Continuity mistake: When Lucy and Ricky are discussing the dance at the beginning of the episode and she turns away from him after she tells him "that's all there is to it," however in the next shot she is still facing towards him.
The Ricardos Dedicate a Statue - S6-E26
Continuity mistake: When Ricky is angry toward Lucy that Little Ricky's pet dog Fred has not learned to be obedient he threatens to return Fred to the dog pound where he says the Ricardos originally got him. However, in episode "6-12", Little Ricky Gets A Dog" Little Ricky admits to Lucy that he got Fred from one of his playmates whose dog had puppies.
The Ricardos Dedicate a Statue - S6-E26
Continuity mistake: When Fred the dog runs onto the couch with Ricky's speech he goes to the right side of the couch and puts his head under a pillow. The shot changes and he is now on the other side of the couch.
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 ★