I may be a touch naive here, but wouldn't a major overload show up on the external pre flight, "she's sitting a bit low on the oleos tonight"
I have never flown a 200T widebody, but I would follow the reasoning that even a 10T increase above max ramp would not manifest itself too clearly on the walkaround. It only equates to 5%, and certainly where I fly, the walkaround is complete before the loading is complete.
RIX