The population of people traveling to countries populated by terrorists and carrying suspicious articles is much smaller than the general population. If we allo

The population of people traveling to countries populated by terrorists and carrying suspicious articles is much smaller than the general population. If we allow the government to conduct any anti-terrorist programs at all, it makes sense to employ such coarse filters to narrow down the number of people they keep an eye on. Unfortunately there's no way to conduct surveillance only on guilty people.