The head of a customer's in-house AV team wanted to personally direct our commissioning. Room by room, hands on, calling the shots alongside my engineers. We spent most of a meeting explaining why that could not work, and I chose to lose the argument.
Our objections were legitimate, not territorial. A customer running a crew he does not manage fragments who owns each room, puts my engineers under two sets of directions at once, stretches the schedule, and forces rework as his calls and ours collide. We commission our way, turn the rooms over, and then work his punchlist. Every time my team pushed back or redirected, he dug in harder.
At some point I stopped arguing the stated point, because we were not going to win it. Underneath the demand was a man who could not accept being shut out of his own project and handed finished rooms to inspect after the fact. That was what needed solving.
So I gave him one engineer. That engineer became the customer-facing path, working rooms slowly with the customer directing the work the way he had wanted to direct the whole crew. The primary team stayed on the critical path and ran the commissioning ahead of them at full speed, untouched. He had his hands on his own rooms, and that was the thing he had been protecting. Just as importantly it gave him a win.
It cost us. That engineer came off the main effort, and because the customer's pass was slow, we touched most of the rooms an extra time behind him. A skeptic can call that caving, or buying quiet with billable labor, and on its face the charge is fair. What it bought was a commissioning that finished clean instead of a crew fighting the customer for the length of the project. I would rather spend one engineer than the whole team's momentum, and I made that trade on purpose.
When a capable customer keeps fighting your process, stop defending the process long enough to hear what they think they are losing. Then meet that need without giving up the work that keeps the project on track. Sometimes losing an argument is the winning solution.