Do you feel safe?

Cato @ Liberty links to a legislative proposal that wouldn’t be necessary in a reasonable world:

H.R. 2464, introduced yesterday, would prohibit the Transportation Security Administration from giving advance notice to security screeners when they are going to be covertly tested.

Does it need saying that tipping off screeners undermines the value of testing? Does TSA need a law to make it not do that?

I already had a low opinion of TSA, so this is more palm-to-the-forehead than surprise. Still, this is ridiculous. Can anyone think of a reason other than pure institutional – TSA and Congressional – incompetence for why the TSA situation is this way?