The chemical test positive happened to me too: they swabbed my bag and the machine beeped and I got a free full body massage.

This was when I was flying home from college for summer.

I explained it as "This is the bag I use for school: something must have touched it during chem lab".

I am a coward for saying this, but your objective when flying is to get to point B. So, make it easy on the jack-booted thugs.

You don't affect change by annoying your local officially sanctioned thug. You affect change by voting.

If you want to make a stand, then come prepared for that: knowledge of law + 24 hours to kill.