Whether it's called "detecting magic", "feeling a disturbance in the Force", "aura sight", "scanning with a tricorder", "using a PKE meter", or just "waving the timey-wimey thingy to check for stuff", detecting (or obscuring) the presence of Powers is a staple of many genres. To account for that, I've included the "Detect/Conceal Aura" power which can be used in settings where it's useful but not automatic. In settings where it would be possible but rarely used (or useful), I wouldn't require casters to expend resources on acquiring the ability as a separate power; instead, I would say that it could be done simply as a normal casting skill roll boosted by Advantage from a Notice or Stealth skill roll (to detect or obscure, respectively). Likewise in settings where this power is used all the time by default, such as Jedi and Sith in Star Wars who are constantly aware of the Force and can detect when others are using it in the same way that normal people are aware of blasters being fired in their vicinity.
