Olfaction is my business and before the TSA existed, the FAA hired me to teach gerbils to odor detect explosives (in checked in luggage) - after the Lockerbe Pan Am catastrophe. Took their money willingly but knew that all the bad guys have to do is seal the expolsives in airtight containers (or shrink wrap) and odor detection is worthless.
If the TSA is actually pursuing the odor detecting dog thing, then they really are less intelligent than the Bad Guys.

As mentioned above, it seems the TSA is always one step behind the terrorists.