"Mutineer 63"
If you had been enough lucky to live in France when there was still a mandatory military service, you would have been examined in front of strangers like you want to be.
When you were called to report at 18 age in front of a draft board commission, you were instructed first to undress completely including all clothes and even watches and so on .. in a waiting room or a corridor according to the facilities of the building where the physical examination took place, then to enter with a large group of young men stark naked like you in a great room, to line up and then to wait your turn to be examined by a commission composed by a military doctor and sometimes a civilian one too and a dozen adult men officers and civilian persons sitiing behind a desk.
Each draftee came in front of the commisssion one by one to be examined. After having been weighted and heighted on the left, he came back in the center of the room and had to stand right in front of the members of the commission to answer to questions and to be examined by the doctor, and he was examined from head to toe front and back.
You would have even been instructed to bend over and to touch your ankles when you were exposing your backsides to the members of the commission, no matter if your asshole was visible from then who mainly were not medical persons to let the doctor check your spine thoroughly as well as he did before for your genitals frontally
At the end, while still turned around back to the commission, the doctor gave you a good slap on your butts while he instructed you to turn again to stand face to the commission and it was finished.
You were examined during about 5 or 8 minutes but you stayed naked in the room for about two hours
And it was was pretty the same when you were called to report to a pre-induction military center for a more thorough examination except that there was only military men. You were also naked in a large group and for a long time
And the same when you were inducted and had your first physical examination after induction.
So you could not miss the opportunities to be naked in front of strangers or with a group of young men of your age at that time, about the 60's and 70's.
And when I read some witnesses on forums, it seems that thre was also in the past a lot of opportunities at sport school or college physical examinations in the United states especially
In France we had also annual school physical examinations for which we undressed in briefs or in the nude all together half of a class so about 15 or 20 students in a waiting room