I watched a show on how they train the dogs. They rub a ball with marijuana and toss it around so the dog thinks he is looking for his ball all the time.
They showed all the tricks used by smugglers and the dog won every time. If you think about using chili pepper the dog is going to start sneezing which makes it look suspicious to the officer. They showed the dog finding a small bud in a coffee can wrapped and sealed air tight in a baggie. The dog found the right can out of 20 and the cans were sealed also. I saw the dog do some amazing things and like I said earlier you can't fool the dog you have to fool the officer.
The other thing you don't understand is the officer can give the dog a command so it looks like the dog found something when he didn't just so the officer can look in that area. It's sad but cops can pretty much do what they want. Anymore the cop can just let the dog out at a routine traffic stop and let him walk around your car and if he senses something they have probable cause and you are busted. That passed in the supreme court so you are screwed.
I know a lot of shows exaggerate some but there is no way I'd bet against the dog, he is going to find it everytime from what I watched. Sealed, unsealed, hidden, anything. I think they even put some weed in paint cans and different chemicals, the dog won everytime without a struggle. Please get the idea of fooling the dog out of your head, it ain't gonna happen.