It used to be that third parties would act as brokers to give vendors an incentive to be honest. For example, my parents had to do several interstate PCS moves when I was a kid while my dad was in the Navy, and each time the movers were hired through the military. They knew there was a lot of repeat business there, so they had an incentive not to screw us. I only remember one mishap during those moves, where a nice desk that was originally from Hong Kong was damaged while the movers were bringing it up a short flight of stairs. They paid the insurance claim without any haggling. The desk was fixed, and I still have it.

Unfortunately, I don't know if even military PCS moves have that level of trustworthiness these days.