It can be very difficult to know what you’re up to.
Benefit: When you make certain skill checks (Appraise and Escape Artist checks, Diplomacy checks to gather information, or Perception checks to notice fine details in the environment), subjects observing or interacting with you must make a Sense Motive checks (opposed by whatever skill you are using) to realize you are doing anything other than engaging in casual conversation or observation.
Adventurer’s Handbook: Genius Guide Volume 1. Copyright 2010, Super Genius Games. Authors: Owen K.C. Stephens and Stan!