Over 400 TSA Officers and employees have been arrested and charged with crimes against the passengers they serve. Don't let a con-artist TSO act "belligerent" while he's stealing your stuff.
Secure your stuff as best as possible and watch it like a hawk. Hope for the best, but plan for the worst. I always opt-out, and I always insist on watching my stuff.
There's another place where the TSA likes to steal: When they pick up a bag for a re-scan, that's a place where they steal things. Like
this TSO who would steal cash out of passenger wallets using that technique. Those few seconds behind the scanner are enough for them to get your things.
The TSA has proven itself to be a criminal enterprise. The TSA used to release statistics. As of 2008, the TSA admitted to 200 arrests for theft alone. (Here's the story on their
own website.) (They aren't counting here the ones arrested for
child rape, or
dealing heroin.)
You are dealing with a proven criminal organization, according to their own website! Watch your bags like a hawk!