Unfortunately this practise of charging for bogus parts and services is rift throughout many service industries including the
HVAC (air conditioning), whitewood and brown goods repairs and other mechanical services.
The worst are the small operations including your self employed "one man band" outfits who come to your home to repair say your fridge or air conditioner.
They have learnt that the quickest way to increase profits is not through extra labour but parts that don't require replacing. So they get lazy as they want "freedom of action" and work less hours and make it up by stealing.
Refrigerant gas is a great one... "Oh, you where low on gas and had to add X amount of gas".... The customer is never going to know if and how much was put in.
They prey on the fact that most people are ignorant on anything mechanical and won't check the work done afterwards. Females naturally become the most victims.
One giveaway that you might be a victim, is when they say you need a particular part for your appliance at home ... And they always seem to just have that exact part in the back of their van without having to order it in and come back later.
What I used to do when I took my car in for servicing at a dealer, is I would get a permanent black Texta and mark certain things on the car the night before.
For example;
1. One wheel nut on each wheel, marked to a particular alignment on the wheel with small black dots... That way you know if they removed the wheels for a brake check or tyre rotation, etc.
2. Fuel and oil filters if they were to be replaced.
3. Windscreen wiper rubber blades.
4. Black dot on fluid levels like power steering, coolant tank, and brake reservoir.
Also check the cabin aircon filter behind the glovebox.
Best thing you can do when taking your car in for any mechanical repairs at the dealer is to get yourself a Polo shirt and get an emblem stitched on the breast pocket. e.g. "Rick's Automotive Repairs & Services" (About $20 at any kiosk type embroidery joint in any major shopping centre).
Then wear it when you take the car in and pick it up... Make them think you are in the trade so they won't try and bluff you.
