Again thanks for you help... one little addition to your long post regarding controls vs. relevant,
You talk about drinking under the influence as being a control.... I would agree... however, if 'under the influence' is clearly defined in the pretest, it would become relevant.... this goes the same for commiting a crime, unless it is clearly defined what a crime is (afterall, j-walking is a crime and we've all done that), even if the examiner adds in the adverb 'serious' (what exactly constitues a serious crime?) the question remains a control.
Clearly defined questions are always relevant...

However, I am having trouble with distinguishing one thing.
Pretest, you admit to taking some minor office supplies.
Have you ever stolen from an employer.... control
Have you ever stolen more then $50 worth of merchandise/supplies from an employer?.... would I be correct in stating that that is a relative question since it is very specific?  Does the number value really matter?  Or is the whole point, that due to your past admission, you already have some stress/anxiety over the question, and thus it is used as a control?