
Visible crew/equipment: When Ethel's on the stoop in front of the building waiting for Lucy and Ricky, right before Ethel asks Ricky about Lucy's driving lesson, just as Ricky drives up we can see cables moving in front of the new Pontiac pulling the car. Then, when Ethel crashes the new Pontiac into the old car, the jiggling cables are again in front of the new car. Lastly, when Lucy finally starts the old car's engine, now there's a moving cable in front of the old car as well. (00:09:50)

Revealing mistake: Look closely at the Ricardos' new Pontiac convertible. There is no glass within the windshield frame.
Visible crew/equipment: When Lucy's sitting on the piano looking out the window at their new car, just as Ricky walks into the living room we can see the shadow of the mic equipment moving overhead, likely adjusting to the actor's position. (00:07:10)
Answer: According to Snopes.com, there is no definitive answer, but the mid-1960s is the most verifiable date with "The Munsters" being cited as the first, although others claim "The Brady Bunch" showed the first couple seen in a double bed. An early TV show from the late 1940s titled, "Mary Kay and Johnny" is also thought to have shown the married couple's bedroom as having a double bed, although probably not with them in it. However, this was when TV was aired live, and there are no surviving episodes, only anecdotal accounts.
raywest ★
Something that is funny is that in the movie "A Christmas Story," they show the parents having two twin beds in their bedroom. In a real situation, they should have shown them having a double bed. Lucy and Ricky had twin beds pushed together in an early episode, which would have been pushing television boundaries in that time.