The court ruling that gave the popos the ability to do a warrentless search also said that a reasonable time to "wait" for the "drug dogs" was about fifteen minutes, now heres the kicker, but the popo does not have to tell you that your free to go. Most people would wait for hours for the back up to arrive or the infamous drug dog, when I believe it was Justice O'Connor who wrote the dissent said that fifteen minutes seemed reasonable period to wait. Putting it in practice is harder than it sounds, it takes nerves of steel to do, but what is better, walking away with a chance to escape or a for sure trip to the pen.