If you lay the law down with them, they perform well.
For me, they show up exactly on time. They removed wrong charges after I spoke with a supervisor.
Maybe if they think you're demented, they might try to pull something.
Keep careful track of your trips and charges.
My bank is aware of them and are watching my account.
I had one strange experience with a driver and REPORTED IT IMMEDIATELY.
Keep records and be proactive.
I call them after trips and get exact charges. If you handle them correctly they are good about respecting you.
GLB Highlander