You can just imagine the dry health and safety rule from the rules and regulations book that is being followed to the letter here:
"Ensure that any obstruction or unexpected obstacle is clearly marked with cones...".
Only they wouldn't say 'cone'. They'd describe it as some "Generic marking and conical warning device with alternating high visibility colour scheme" or worse.
Now I'm sure that in their little book a "ruddy great 736 with a large blue trailer holding up the wing" comes under the heading of an unexpected obstacle or some such
