Whether people fill their tanks up when they're partially gone or completely empty doesn't change the rate at which they use gas, so I'm missing the logic in that statement. My experience with all the different cars I've had is that the gas gage will move at different rates at certain points in the tank. NOT because they want you to think you have more gas, but because the shape of the tank and the position of the sensor influences where the gage thinks the fuel level is.
After driving my Protege on long highway trips every week for a year I have become accustomed to how much gas is left at certain points on the gage, and made my estimate based on that.