Not true, I've got a hell of a story to support my claim.
Long story short, a very generous amount of insanely smelly stuff in my tailgate, half in my snowboard boot and the other half in my roommate's duffel bag. Went through a spring break road block at 11pm. A K9 ravaged my car and picked up no scent from tailgate, however produced a false positive on my driver door. In total, a k9 and over ten cops simultaneously going to town on my car and we still drove away scott free and with every piece of green left untouched.
Moral of the story is canines are not perfect, cops are even more imperfect. If you want to keep yourself out of trouble and still find the need to transport it, at least keep your forward cabin (front and back seats) clear. Even in an open tailgate as with an SUV, officers will first probe for solid suspicion before searching that area. This idea has kept me out of harm's way more than once.
Haha looking back at this night, this was by far the best quote of the evening. This was when the 2 passengers and I were all being interrogated separately, I was outside next to my tailgate and my 2 roommates were towards the front of my truck. I can hear the officer asking my roommate about the truck so I listen in:
Officer: Now what's that thing there, a scuba?
Roommate: Its his he would know (points to me)
Me: (laughing) Its called a snorkel but yeah same function.
Officer: (angered at me laughing) Well whatever it is it'll look good in our impound.