Last time I went through SEA, it was in full force there.

Including blaring repeated announcements in the sterile areas reached only by a train ride - repeated loops about 3-1-1 restrictions beyond the checkpoint.

??!! Do they really think someone who has passed the checkpoint, taken a train, reached the gate area and discovered - gasp! - that he/she has something in his/her carry-on that can, in fact, be purchased or stolen from any number of shops and restaurants in the area - do they really think someone is going to hear the announcement and take the train back to the checkpoint to voluntarily surrender themselves for re-screening?

This is in addition to taped loops (as you noted, all loud - thankfully most of the CNN/Fox monitors are kept a bit quieter these days) with a welcome from the clown in charge, taped loops about 'security alert - report abandoned bags, bla-bla'. All repeated by a man and woman barking in their best designed-to-be-officious and grating outdoor voices, along with the unctuous oily voice of the Port of Seattle director.

Somehow they can always keep these obnoxious taped loops functioning in every corner of the airport (even the toilets!), but they don't seem to be nearly as good at ensuring complete coverage and reliability when it comes to checkpoint and security cameras.

Nothing but noise pollution.

ATL has one playing that starts out something like: 'security alert' - and then goes on to the usual -bla-bla. Good way to ensure that if there ever is a real security alert, people will just think it's more of the same.