As a former mechanic, at least my shop would occasionally refuse to let a vehicle leave the shop- the one example that I remember most clearly was a SUV that came in for an oil change. The owner was planning on a 800 mile trip with their family and wanted an oil change before leaving. One of the wheels had a serious suspension problem, and would likely fall off shortly & cause a rollover.
We weren't going to let that truck leave our shop w/o getting fixed, none of us wanted dead kids on our conscience. We extended credit to the customer & cut our rate so the owner could afford it. Point being, in this case we definitely knew better than the customer, somehow they didn't realize a wheel falling off at highway speed is dangerous. P
However, that was a very rare situation. If a customer insisted they wanted work done that we didn't feel was necessary, we would tell them so but still do the work if they wanted it.
We weren't going to let that truck leave our shop w/o getting fixed, none of us wanted dead kids on our conscience. We extended credit to the customer & cut our rate so the owner could afford it. Point being, in this case we definitely knew better than the customer, somehow they didn't realize a wheel falling off at highway speed is dangerous. P
However, that was a very rare situation. If a customer insisted they wanted work done that we didn't feel was necessary, we would tell them so but still do the work if they wanted it.