That's another great question.
When I left the military, I was given a piece of paper that said I had top secret security clearance. When I went to the RCMP they ran me through another security clearance. I did another interview. They ran me through another security clearance. Then I went to another agency and they put me through.... The RCMP must have been sick and tired of seeing my name coming through for security clearances because they were constantly asking. All they had to do was punch in my name and say I already had it and ask if anything had fundamentally changed in my life and I would have said no.