The Transporter Malfunction - S5-E20
Continuity mistake: Sheldon opens his transporter box and takes out Mr. Spock, while making a big deal about it remaining mint in box, unopened. Later, he makes a big show of using an exacto knife to gently open the box with Spock in it.
Chosen answer: It does. The variable cleanliness of the cab and the habit of taxi drivers to engage customers in small talk would be too much for Sheldon to handle, and not an option for him.
Captain Defenestrator