Interesting statement that the bags are all weighed. I once volunteered to be bumped because our plane was weight limited, not seat limited. Three others also volunteered. They only needed to bump 3 - I was selected to go on the flight because I only had a carry-on bag and the others each had checked a bag. I commented, "Why me? I weigh over 200 pounds and none of the 3 young ladies who were bumped were over 120. It was the old standard weight deal - a passenger is 170 pounds (at least back then) no matter what, and a checked bag is xx pounds (can't remember the figure). Of course there are safety margins so I knew there was no problem with me being on the plane. I have only been on one flight where they actually weighed every person and every bag. That was a very small airline in Australia that had lost a plane 2 months earlier. Surely landing gear sensors would be relatively easy on an airliner. Even on the heavy equipment on which I work we have bucket load sensors so an operator can load a 400 tonne truck to the max and not seriously overload it.