With my earliest physicals I can remember, school physicals, one year I was told to undress completely at the beginning, and so I was weighed naked. Then another year I was told to take off everything except my socks, so that time I was pretty much naked.
There were times at our family doctor where I was naked for the physical, and weighed, in the doctor's office. Then, as a teenager when our family switched to another medical practice, with three or four doctors, the scale was in the hallway, but I was always weighed in at least a gown, or still clothed.
More recently, at physicals for studies, I have been weighed naked, sometimes, but always in an exam room or office. If the scales are in the hallway then it's done before undressing, just shoes off, or in a gown. Almost two months ago, I was being screened for a dermatological study, and I was asked to undress completely, put on a gown, then led out to the scale in the hallway holding the back of the gown closed as well as I could. They said they wanted me undressed so they would get the most accurate weight. Later, I was leaving as a woman probably in her 60's was being weighed in her gown, which was not really closed in the back, as she tried to hold it with one hand.