Here is a great example of how people use 5S thinking and visuals to control the work environment:
What are the markings on the tarmac?
A closer look reveals that the markings represent different airplane types. Also, the ground crew placed the wheel chocks near the line he needs the plane to stop at. For you SMED (or quick changeover) people, this means taking a normally internal changeover task and converting it into an external task. In other words, do as much preparation for the job as possible before the job actually begins.
Here comes the plane. Let's see if the ground crew got it right...
Bingo! Nice job! You can use this example in your visual control training to ask the following quesiton: What sort of problems might occur if this visual control were not in place?