As an in-experienced fire safety adviser working at a local University years back I used to take pleasure in walking around my little empire, with my clipboard, telling off all the naughty professors, academics, and students who propped open fire doors.
One day I removed a wedge from one professor's door - As the Uni was such a big place and i hadn't met this particular professor before.
He was most annoyed at my removing his wedge and snatched it off me, inserting it back under the door. He then drilled me down for daring to remove the wedge.
Not to be intimidated I quoted chapter and verse about fire safety legislation at him, and waggled my finger alot.
What I didn't expect in response was a damning fifty mintue lecture on fire behaviour, physics, chemistry, and every reason under the sun why that particular fire door wasn't a fire door and was not required for MOE purposes.......
You see because his door was propped open I had failed to see the sign declaring him to be head of the health and safety school within the Uni. It turns out that he was an expert in Physics, H&S, H&S Law,fire safety, and was a respected expert witness.
There is a moral behind that story - not sure what it is though!.