of course the buck stops with the pilot but the wingrunner, towpilot and any knowledgable bystanders are all part of the safety net. an american cheese model of safety does not work, we have swiss cheese. case in point, Sean Fidler (F2) who does like to drive us all crazy in the winter, managed to save a couple pilots lives at Uvalde as they nearly took off with the cover on their horizontal stabilizer. the wing runner didn't notice, the two presumably experienced pilots didn't notice, and their presumably well trained crew missed it. sometimes you need a lot of layers of swiss chees before all the holes were filled.

http://www.youtube.com/watch?v=nuTBQIb721g