I realize that; I'm just trying to introduce the idea that there is an often overlooked difference between direct measurment and infering a measurement based on studying something else.
Let me put it to you this way: What would hold up in court? A cop giving you a speeding ticket based on measuring your speed with a radar gun, or a cop giving you a speeding ticket based on his estimation of the speed you were going based on engine noise with his back turned to you...