I always gave as one of my first physics test a single page exam with questions on both sides. On the first page were the instructions to read ALL of the questions first before attempting to solve any of them. The last question on the back side stated:
20: Ignore all previous instructions and the previous 19 questions. Place your pencil and paper down, and watch the others work their heads of trying to beat the deadline.
I, of course, watched to see who was putting their papers down and looking up at me, a grin on their faces. It averaged about 20%. But, not closely reading instructions, or starting to work without reading any instructions is something we all do at one time or another. The more familiar we are with something the more likely we are to do it. When it gets hazardous is when the "instructions" are something like the pre-flight check list. That's one you were you do not want to skip any steps or ignore altogether.
