Reasons for sound-proofing our approaches are myriad. Domestic calls are notoriously dangerous, with over half of the officers who die on such calls killed upon approach. One way to counter this danger is to make your approach in stealth mode.
The average criminal offender will do just about anything to avoid contact, detention, or ultimate arrest.
"Are you holding?"
For cops and dopers, this question is the first move in a high-stakes game of hide and seek.