Might be a good idea that the walk around check would be more beneficial when service vehicles and support peoples have departed the vicinity of the a/c. Just a though.
We have that covered. We carry two ground engineers everywhere, and they do precisely as you have described...a late stage external inspection before the final door is closed.
They also personally close
all cargo doors.
We leave
nothing to chance in the ad-hoc charter business.
Nothing
We have all experienced personnel at our company, no 'instant experts' allowed.