Assessing the mileage of the car according to its windscreen?

How can you assess the mileage of the car by examining the windscreen? Here are a few tips:
- When the mileage is bigger than 100 000 km, the windscreen becomes matte. The firsts signs of wear become visible.
- When the mileage is bigger than 200 000 km, the windshield can have circular scrapings.
- The frequent use of wipers can cause scrapings on the windshield due to the wipers being worn and due to the sand getting under the wipers.

For me personally, the mileage is not important. The car is supposed to be driven. It's only important whether it's in a good shape and whether somebody has been taking care of it. However, when you find out that the seller is hiding the real mileage of the car, you know he's not trustworthy.