It's unfortunate that these four individuals have now given TSA another black eye. However, there are some lessons-learned from this:
As Spiff said, it's always a good idea to place your valuables inside one of your carry-on items instead of leaving them inside an open tray for all to see. While the article points to TSA employee theft, it omits the other possibilities of fellow passengers accidentally picking up your valuables (often happens when someone picks up items for someone else) or thieves who take advantage of the temporary confusion to steal valuables (TSA screeners wouldn't know whose items belong to whom).
Always be present whenever ANYONE searches your bag. I always make it a point to wait until a passenger is ready for me to begin my search; however, it is not unusual for a passenger to tell me to hurry it up and get it over while he or she turns away to put on his or her shoes back on, belt, etc. (I also have a habit of turning my palms up after I've finished searching a bag; it's a technique I learned from a fellow screener who used to work in a casino.) These are measures I take to protect myself from false accusations. However, as I mentioned above, I am still amazed at how careless people are whenever their property is being searched. You have the right to observe your property being searched: please take full advantage of it.
Checked baggage screening depends on the configuration of the TSA baggage pod. In some airports, the bags are screened in the public area and then turned over to the aircraft carrier to be loaded onto the plane. In other airports, bags are screened behind the ticket counter out of public view and then loaded onto aircraft. Whenever possible, you have the right to watch your bags be searched. This can be accomodated in the first type of baggage pods I described; however, the same cannot be done for the second type. We offer this courtesy in San Antonio since all but one of our baggage pods are located in the public area. You would be amazed at how few take advantage of this courtesy; a great majority of people simply drop off their bags at the TSA screening pod and then walk away.
Am I implying that TSA screeners are not to be trusted? Not at all. I'm just saying to follow my Dad's advice of "keeping honest people honest."