I am not trying to defend the TSA, mind you, but it has long been their practice to alter/add additional security without announcing/publicizing it. This can be bothersome, true, but one doesn't want bad guys to be too sure what will be expected of them as they try to pass through Security. As the OP notes, you can still get through Security without having a second ID, you'll simply come under additional scrutiny. Again, let me reiterate, I am not advocating such measures nor suggesting they are effective; I'm merely pointing out that they are nothing new.
Yep, this almost as effective as not putting the names of real bad guys on the no-fly-list so they don't know we're on to them.
x 6.02E23
Couple of months back, TSA at MCO airside 1/3 would not accept my INS Green Card for ID, crayoned "SSSS" on my BP, searched me down in the pre-WTMD line to ensure I went to the plastic penalty box, and then engaged in highly effective additional screening. Great time was had by all. Best line was from a 3 striper, who, when I demanded to know exactly what was wrong with my DHS issued ID since I had used it but a week earlier to re-enter the country stated, "well, probably nothing, but the call is up to the guy doing the document check."
Seems to me a several year intensive instruction program couldn't raise some of these buffoons' performance to merely unsat levels.
