I would think it would be quite the opposite -- when advocating the PATRIOT act, which created the DHS and the TSA and implemented a number of measures that reduced individual liberties and privacy, the Administration made repeated promises to Congress suggesting that they were offended at the very idea that the new powers, if granted would be ever be used for anything that wasn't strictly related to fighting terrorism. That explicitly excluded even using these powers for purposes of fighiting violent, but non-terrorist, crimes, so in response to the poster who asked what the TSA would do if they found bloody clothing, the answer the Justice department repeatedly gave Congress both informally and in sworn testimony is "absolutely nothing". You therefore certainly cannot begin to defend using it to enforce misdemeanor statutes, such as those for drug possession. So if word got out that they WERE in fact doing this, I would expect the public reaction to be one of outrage over breaking trust.