I mentioned before that cops are generally able to pick other cops out of a crowd. Bad guys have the same skill, as a matter of survival. Cops are also pretty good at picking out bad guys. Granted, some "picks" turn out to be nothing untoward, but lots of legit, up-to-no-good bad guys have been apprehended by this kind of observation. The U.S. Supreme Court even went so far as to recognize the observation skills of experienced officers in the decision of Terry v. Ohio.

Is there potential for abuse in deploying a covert observation system in an airport? Sure. Would it be effective in stopping people who were planning to do something illegal on an airplane? Probably. However, I suspect that relatively few innocent parties would be stopped, and that the system would be effective. I am constantly appalled at the attitude of many of the members of this forum that regard the first class section of an airplane as their birthright, and kick and scream at the mere suggestion of anything that might keep them for getting to the big seat as quickly and surely as humanly possible. There are people out there that want to do us harm, and we are foolish to drop our guard and make it easy for them to do so.