Yours was a valid question and I am interested in the responses. However, it seemed to me that you were almost advocating signing for the aircraft as long as everyone else has done what they signed for....
Also, you say that you are happy to arrive at the aircraft and delegate the walk round - and that is what concerns me with the actions taken in this case and the AAIB report. Do BA (or other operator's) Captains routinely delegate first flight walk rounds? Why? The AAIB report did not consider the pros and cons of those actions (preferring to concentrate on shortcomings in engineering management, which do need addressing) - I think they should have. My opinion - I am interested in what others think about it.