I work in the airline industry along-side TSA and I can tell you they don't give a damn what is in your luggage as long as it doesn't set of their sensors. They are only looking for weapons, combustibles, explosive & hazardous materials. Same goes for LE-K9s.
I escort people through security regularly in wheelchairs. These folks sometimes have bunches of drugs and sometimes syringes in their carry-on. They get searched and no questions are asked about the drugs. They are not looking for drugs. It's about the safety of the other passengers and flight crew.
Obviously flying internationally with contraband is a different situation entirely.