Schneier on Security: "Clear" Registered Traveller Program:
The truth is that whenever you create two paths through security -- a high-security path and a low-security path -- you have to assume that the bad guys will find a way to exploit the low-security path. It may be counterintuitive, but we are all safer if the people chosen for more thorough screening are truly random and not based on an error-filled database or a cursory background check.
I think of Clear as a $100 service that tells terrorists if the F.B.I. is on to them or not. Why in the world would we provide terrorists with this ability?
We don’t have to. Clear cardholders are not scrutinized less when they go through checkpoints, they’re scrutinized more efficiently. So why not get rid of the background checks altogether? We should all be able to walk into the airport, pay $10, and use the Clear lanes when it’s worth it to us.