What makes sarging of such interest is the blend of psychology and acting skills required to pull it off. That spontaneous meeting with that dark dangerous stranger who was charming, witty, fun, mysterous, and understood you at a deep emotional level, touched your soul, and disappeared never to be heard from again actually was a persona that took hours of rehersal and days of study.
There are actual field courses, books, and whole underground networks devoted to the topic. What's so surprising is the success rate. When behavior is understood and modeled, it can be easily manipulated.
Sarging techniques also have other applications, such as keeping an existing relationship fun and interesting, or if you are a performer, connecting with your audience better.