I think this thread misses the whole point.
1. No one should be detained for "acting suspicious unless a clear and credible threat can be articulated. For the police/security to hide behind operational security is crap. If they truly told the man they did not know what he was doing but to stop doing it is shows that have no grasp on reality. If I were told that I might fall down laughing.
2. For an airline to deny access to flights based on unspecified "suspicious acts" with no further detail is at best poor business practices and at worst nearing discrimination. Of course they have the right to deny service to anyone but they should exercise restraint or they may not have anyone to exercise the right upon!
3. Freedom is a precious thing and should not be compromised at all. Our "protectors" should keep this in mind as they do their jobs. It is a difficult job with hard decisions to make but remember the basis of what America was founded on.