>Ask the person to write out each and every step required to

That's very wise. It's an eye-opener to go through such an exercise.

In one of my first writing courses, our very first assignment was to write instructions for making a peanut butter sandwich. After collecting all the papers, the teacher pulled out jars of peanut butter and loaves of bread and proceeded to follow instructions we'd just written.

"Put peanut butter on bread"

She picked up the jar and slammed it down on the loaf of bread.

It was an incredibly effective demo, and taught us a LOT about communicating clearly. ;-)