[mh-]

It hasn't.

https://www.cnn.com/2019/12/20/politics/tsa-whistleblower-ai...

In 2015, agents with Department of Homeland Security posing as passengers snuck fake explosives through the security lines of several of the nation’s busiest airports. During the test, TSA officers missed 67 of the 70 fake weapons that went through the checks – a failure rate of 95%.

[pashamur]

I wonder if the TSA has some signaling effect though apart from the actual efficacy of the security theatre. Even if it catches things rarely, the fact that it exists makes people more aware and potentially look out more for abnormal behavior in airports (and catching some things some times still probably acts as a deterrent - at least more so than not having the security theatre around)