The watch industry used to vet repair Watch Repair shops on the guise of "Quality Assurance". They would require Watchmakers buy their expensive cleaning machines, and a bunch of other pricy tooling, and requirements; in order to procure parts. 90% of watchmakers couldn't get a parts accout, and the watch companies loved it. it meant more after sales/warranty business.
This was because they didn't want to sell parts to anyone. They wanted to do the repairs
For a few years, certain Watchmakers kept up with the demands from Rolex, and The Swatch Group.
We were just happy to be able to get parts.
About 15 years ago the watch companies just decided not to sell parts to anyone.
That whole Vertical Intregtation consumer ripoff.
I am very leary of any company that wants to vet their repair shops for anything, other than maybe medical equipment.
They will supply the schematics, but they don't want to make it easy.
(I'm pretty sure I'm hellbanned again?)