Orchestras stand when their conductor walks on stage. I’m not sure if that’s deference to the conductor or acknowledgement of audience applause.
Here Comes the Judge is a 1968 song by legendary comedian Pigmeat Markham. It become one of comedy’s first memes when Sammy Davis Jr. made it a catchphrase on the TV show: Rowan & Martin’s Laugh In.
Fiddler on the Roof.
In Thailand it is reversed. Younger people never stand taller then the elders. It is OK if they sit when an elder enters but if they are standing the younguns bend over in a slouch so they are shorter. When I visited Thailand with my Thai wife I was double blessed - older and a visiting dignitary. I have never seen so many crouched down people before or since!
My veterans often stand if I come into the classroom after they’re seated.
Ah – Tradition! I get it.
Funny, I thought it was Pratchett, too. Seems like something he would have written.
Nah. This is Pratchett:
" if there were two things the city liked, it was tradition and goddesses, especially if the goddesses were a bit short on chiffon above the waist.
or
You did something because it had always been done, and the explanation was ‘But we’ve always done it this way.’ A million dead people can’t have been wrong, can they?
Thanks! That guy was a genius.
I prefer that attys NOT stand when I enter hrg rooms for the admin proceedings I preside over. I’d prefer that a representative demonstrate their respect for my office and the proceeding via competence and preparedness.
The ones most likely to stand, use flowery language, and demonstrate various lawyerly formalities are also the sort most likely to say, “With all due respect…” When they really mean, “Fuck you, asshole!”
Has anyone ever used that phrase in a manner actually intended to convey some level of respect, or do folk just use it to signal that they feel the person addressed is “due” no respect? 
When I use it, it is to indicate respect for the judge’s comments, but explain why I think there is an alternative approach. It’s in no way meant as an insult.
I prefer “Respectfully…” for that reason.
Thus the “should.”
You may think that. And I have every reason to believe you say it in a respectful manner. I’m just offering a perspective from my side of the bench that as a general manner, when someone prefaces their remarks with, “With all due respect”, that basically signals that their following remarks are going to be disrespectful. Works pretty much the same in non-legal exchanges. “With all due respect - get your head out of your ass.”
I don’t really see the need for the prefatory language. It adds nothing. Theater, from watching lawyers on TV. Oughtn’t we presume we are being respectful of each other? If so, just say the words, and we’ll each decide what we feel they are worth.
Don’t get me started on, “Without further ado…” 
The thing that bugs me is starting every argument with “Just briefly, your honor…”
What would be an example of “Ado?”
I can’t answer the OP’s question specifically, but there are jobs where you stand when such-n-such person enters the room so that you will be immediately ready to carry out whatever instructions you are given. You are on your feet, paying attention, and ready to go.
I went to a Catholic elementary school back in the dark ages, and we had to stand up any time a priest or nun came into the room and say “Good morning (afternoon), Father Soandso” or " Good morning, Sister Soandso."
Just because people are equal does not mean that their jobs or positions are equal. I’m guessing that (A) either you don’t show this attitude at work that you show here, or (B) you’ve gotten fired from a lot of jobs.
I did, too. There was one nun who insisted that we chant (of course we did it in a singsong voice), “Praised be Jesus Christ, good morning Sister Mary Elephant.”