Actually, this does make me feel more secure. If the "random" checks are done only for those individuals who might possibly be suspicious, and are never done for people who look like they could cause no trouble, the next incident will be perpetrated by people recruited from the pool of people that won't get checked. Assuming they don't have enough people that are picked due to specific criteria (such as one-way tickets, cash purchase, etc.), the remaining people chosen for secondary screening should be completely random, with nobody excluded.

Based on your message, I have a question: do you think that people with an American flag pin on their sweater are less suspicious?