Jimny, I am sure DB does a walk-around every flight .... he just doesn't climb up on top to re-open cowlings that have already been opened the previous day's post flight, and again in the morning and signed for by a qualified engineer. Sounds like he was in an Air Force - you know where the orficers job was just to wiggle the sticks, don't you know!
I was a grunt and so clambered on top for years; but after quite some time in established civilian offshore companies, and with age .... I see no point in placing myself as well at risk - and have every confidence in the safety systems procedures that now permit this - whilst I am at a base with maintenance personnel.