I have to toss my thoughts in on this, I have worked for a forklift dealership for over 10 years and when they said they were going to put GPS's on our service vans quite a number of the guys did not like the idea. Me? I forget it is even there anymore.
If the tech does his job, and management does not micromanage the system it works fine.
Does the company I work for use it for dispatch? Sometimes. Do they use it to check on guys? They spot check from time to time.
GPS is a tool just like any other.