I know several people whose eyesight is legally within range of being able to drive yet I can see farther than them.

Anyway, neither of those points that you made have anything to do with the question at hand.

Post a law, ruling, judgment etc stating that speed limit are established once you see the sign and not once you pass it.

Edit: Furthermore, you say you can be ticketed without seeing the limit. That's sort of my point. You've passed a sign at some point, whether you saw it or not. You have to go that speed. Once you get to another speed zone, you can or must accelerate or decelerate based on that newly established zone.