Many airlines use the profiling system whereby the prospective passenger is subjected to a security interview which is intended to unearth any "suspicious signs". A passenger who either demonstrates a suspicious sign or whose answers to security questions are inconsistent are interviewed in more depth, until the suspicious sign is either resolved to the security agent's satisfaction, or the passenger is then subjected to further security treatment (ie., Body Search, full baggage search etc.
Naturally, some passengers find such techniques repellent, and many choose not to fly. However, it is this system that successfully caught the young lady referred to, whose name I believe to be Rose Murphy. I like security. There are too many nutters out there. So, when asked, answer the questions folks!
Tailwinds