I have read this thread at length and feel I should make a comment.
I run a liveaboard boat, and before we leave the pier I have the customers set up their equipment. This is done under supervision of the diving and deck staff. I have found it very beneficial to watch a customer set up their gear as an aid to checking how competant they are. I have seen divers with 100+ dives putting their regs on the tank before the BCD! I have seen divers putting 7 kilos on their weight belt when they need only 3 kilos. Myself, the dive staff, and the deck staff are always on hand to help if it is needed. I find that on every trip we will have to assist at least 2 people in their equipment set up.
In between dives we ask the customers to remove the first stage from the tank so that we can fill it up. The deck staff fill the tanks and reconnect the regs. Before entering the water I ask all divers to do a buddy check. On the dive platform itself, the deck staff check that everybody's air is switched on, including the dive staffs.
Many of the posts on this thread seem to relate to people not trusting the deck staff/DM to know what they are doing. If you do not trust the deck staff/DM, why are you diving off their boat, do you ask for a tour of the engine room to ensure all the parts are working? Do you check the kitchen for a health and safety sign?
All of my deck staff are Rescue Divers and have intimate knowledge of scuba gear. They service my regs for me! They have fixed customers regs free of charge.
At the end of the trip, the staff assist customers in packing their dive gear. If the customer wants help we give it. If the customer wants us to do it all, we do it. If the customer does not want any help, we leave them alone, we do not take offence. We are being paid to take care of the customer and give them a great trip.
If you want to set up your gear, you should be able to. If you want someone to take care of it for you, that should not be a problem. The most important thing is to do a full pre-dive safety check, no matter who sets up the gear.
Dive Safe