No, not MC mechanics, but I'm sure there are plenty of them also. This is a recent experience with my daughter's car.
She took it to a shop for a squealing noise coming from one of her wheels. A big chain repair shop gave her a $600+ estimate for front rotors, calipers, and pads. Another estimate from a different independent shop was $500+ for the same. She asked if I would take a look. All I found was the right REAR wear indicator rubbing on the rotor. The front brakes were in perfect shape. One of the rear pads wore down prematurely due to improper installation - the pad nubs were not in the caliper grooves so it was tilting the pad. I replaced the pads and rotors for her for less than $100.
Both shops said they thoroughly checked her entire brake system to determine the cause. Complete bull****!
THIS IS WHY I DO ALMOST ALL OF MY OWN MECHANICAL WORK, ESPECIALLY ON MY MOTORCYCLES. (sorry for yelling)
If you ever find an honest mechanic, cherish him (or her). Bake him some cookies and send him a Christmas card. If I ever do, I will.