Not in my lifetime
If a yard requires their employees perform all the work they should be required in writing to be responsible for their employees' damage. The sword cuts both ways and without such language in the contract even by addendum I'd walk.
Here's a situation that happened to me:
I built my own Westsail in the 80's, poured my heart and soul into it. I sold it as part of a divorce settlement to a nice couple on the other side of the country. Once money was transferred I became the new owner's West coast agent for all matters boat related, power of attorney included. I arranged for a yard in Newport Beach to decommission the boat and load it on a cross-country truck. Their policy, as has been the topic here, was all work had to be done by yard personnel.
Their first task was to remove the mast. After arriving at the yard I walked over to the boat in the slip, the mast was supported by a crane and I witnessed a yard employee undoing the forestay (without removing the turnbuckle cotter pin and slacking the stay) by beating on the clevis pin with a hammer and screwdriver, this on a custom chrome plated bronze casting. And I mean custom, I made the pattern, I had it cast by a foundry, machined, polished and plated. There were no replacements.
I ordered him to stop immediately (fortunately el senor comprende anglais muy bueno) and stormed into the yard office where I absolutely Chernobyled. The only remedy I would accept was their personnel would not set foot on the boat again, I was to do any work required from that point on including supervising loading the boat on the truck. As I was the original builder with a master carpenter's certificate from the USCG, the yard owner finally agreed with his apology.
If my actions spoiled any future relationship with the yard, no problem here. What are the chances I'd ever go there again?
The point is, does requiring yard personnel to perform all work also require you to accept hammer and chisel quality? Not in my lifetime.