This is one of the questions to which the examiner will expect you to answer "yes" during the pre-test, and then he or she will ask you for details.  For every instance you mention in which you lied the examiner will behave as though it is hovering on the brink of being a deal-breaker.  The idea is to eventually get you to stop admitting to previous lies so that, during the phase of the test where you are actually hooked up to the polygraph and you are again asked the (obviously very broad) question of "Other than what you've told me, have you ever lied to a parent/teacher/police" you will answer in the negative, and the examiner will assume you are lying.

The examiner will note your responses and will compare them to your responses when answering relevant questions.  If you responses on the relevant questions are greater than your responses when "lying" on the control question he or she will believe you to be answering deceptively regarding the relevant questions.