Yep, I knew this would happen.....
I was sitting in our airline's mandatory Security and Hijacking class for post 9/11 responses. One of my thoughts on the stuff presented was "this is great, but who is telling the GA folks to be careful".
I'm not nor should any other 121/135 pilot spill the beans on this public forum about the new TSA security rules. However, I will say that for any GA pilot who knows the codes above, you should realize that they have some new meanings and you will most likely get an escort.
This is why AOPA is telling you to understand the interception procedures. You not only have certain squawk codes but there are certain words you could inadvertently say to the wrong controller and get the same greeting.
So......just do what the book says. If intercepted, follow the directions provided by the nice DoD guys. Don't grumble, don't be surprised, don't argue. The 9/11 event and the advent of the TSA has changed and will continue to change the way we live and fly. Right now, a very paranoid group of security guys has the ears of the President, Congress and most of us.
But when you are talking about using transponders, just remember this one little bit of info from the morning of 9/11 - when the weapon planes were taken over and just before turning to their targets all the transponders were turned off by the hijackers. One of the planes had squawked emergency before turning. Get the picture?