I got busted with a car load of mates in the back of a nightclub car park sharing a joint. The cops knock on the car window and as the we opened the doors to get out smoke was pouring out like a smoke machine. Fortunately the guy with smoke in hand swallowed it, and the baggie was quickly thrown into a storage compartment in the dash (separate from the glove box). The cops gave us the usual lecture, searched the car and found nothing (to which we were surprised since there was a bag of pot in the dash). The cop clearly disappointed called in the dogs and gave us a chance to come clean before the dogs rip the car to shreds. We stay tight lipped, and the dogs go in, sniff around for a bit, but find nothing (even more surprising since these were dogs right?).
So we got a lecture and a warning and sent on our way. Got home pulled out the bag and finished off the stash. That was 25 years ago, but taught me a great lesson in security theatre, especially police dogs (which are generally trained for perp restraint and intimidation than drug sniffing).