Ever since the introduction oF CAD in ALL spheres of manufacturing, the VERY important role of the checker had been undermined. Progressively, all CAD product manufacturers have added "self checking" features into their products. In the early days, these were very basic, and were nearly always subject to debate on accuracy. Nowadays we are being led to believe that they are the "bible". Not true, nothing that the programmers can instigate can equate to "gut feel", "eye for error", "true professionalisim".
We live in a world that demands excellent results instantly, yet in most cases, the basic training does not exist so that the operator can mentally visualize potential traps along the way. And to add to the mayhem that is increasing in all areas, "CAD Operators" are increasingly being given the design roles - they are cheaper (initaily). I too started on the "board", could accurately forecast timeframes, and even though I strove for perfection, I occasionally tripped up. Thank God for "The Checker".
Let's not kid ourselves, we must be vigilant, trust the product we use to achieve our aims, but we must NOT retire the Checker.