It hasn't often been approached as you have so done.
My experience outside of the US for weeklong+ stays? They study how you set up your gear the first day. Then after that, no matter how weird you thread stuff around and position it on the tank- they will duplicate it almost to perfection. Always worth checking, but that's what these guys do 24/7/365.
If a dive op won't take your direction and keep their hands off your gear if you so direct, find another dive op.
There are some exceptions. In the deep vee hulls of outrigger boats in the South Pacific to Africa, you would do well to sit where you are directed and try to stay out of the way. Even after they change out your tanks in this difficult environment, you will be allowed the opportunity to look it over and make adjustments and checks before being assisted to put it on.
How the US Navy does it:
"
However, it’s great to have the services of a tender. Each diver has a dresser or, more properly, a tender who is responsible for seeing that the diver is safely dressed. My tender is one of the instructors and hands me the weight harness."
As your dive experience broadens and as you go to less comodious places, you'll likely well be ready to accept the hand of the Boatsman, assisting you in whatever way they can to gear up.
From the movie Stripes: The name's Francis Sawyer, but everybody calls me Psycho. Any of you guys call me Francis, and I'll kill you.
Leon: Ooooooh.
Psycho: You just made the list, buddy. Also, I don't like no one touching my stuff. So just keep your meat-hooks off. If I catch any of you guys in my stuff, I'll kill you. And I don't like nobody touching me. Any of you homos touch me, and I'll kill you.
Sergeant Hulka: Lighten up, Francis.
By all means, check it over, ask them to do only what you instruct, but if you want them to leave something alone- just ask. But understand that in some adverse conditions, you will be ably assisted into your gear by a guy who's been wet more than all of us put together. Let them manage their environment as the situation dictates.