A frequent defense proffered for feel-good, nonsensical, expensive "security theater" (like taking away air travellers' nail clippers) is that it can help us all to "feel secure." Bruce Schneier just blogged these thoughts on "feeling secure" from Bill Mason, a jewel thief.
Nothing works more in a thief's favor than people feeling secure. That's why places that are heavily alarmed and guarded can sometimes be the easiest targets. The single most important factor in security — more than locks, alarms, sensors, or armed guards — is attitude. A building protected by nothing more than a cheap combination lock but inhabited by people who are alert and risk-aware is much safer than one with the world's most sophisticated alarm system whose tenants assume they're living in an impregnable fortress.
