False Sampachi

When I visited one of our clients the other day, I heard the term "false sampachi".
He said it is "a baseless number that you put in for the time being" when you are worried.

Come to think of it, "inspection specifications" often include "±0.03mm" or something like that (lol).
I wonder how much meaning there is in measuring hard and then comparing it to this unsubstantiated number and discussing "quality"....