95% of the time, TSA agents were not able to find the fake or concealed weapons that investigators who were posing as passengers took through security at busy airports in the USA.
100% of the time, they take my water bottles.
Honestly, I think we already know this. I regularly pack my nail clippers and ever pocket knife in my carry on because I know it isn't going to be found, and even if it is, whats the $3 that I will lose?
The focus of the TSA in the US seems to be on providing a sense of safety as opposed to actually finding and stopping any threats. And now that the numbers are out (67 of 70 agents failed to detect anything suspicious), I feel less assured in their security procedures than ever before.