P 303 of paperback PoA: Professor Flitwick says that the Fidelius Charm   
   involves the magical hiding of a secret within a person, known as the Secret   
   Keeper.  The information is impossible to find, unless the Secret Keeper tells   
   you.  For example, the FC    
   was used to hide the Potter family (James, Lilly, and Harry) from Lord   
   Voldemort.  As long as the Secret Keeper (thought to be Sirius Black at the   
   time, but later revealed to be Peter Pettigrew) kept his mouth shut, LV could   
   search the Potter's village (   
   Godric's Hollow) for years without finding them, even if he had his nose   
   pressed against the Potters' sitting room window!  Does the fact that LV could   
   search the entire village without finding the Potters mean that the Potters   
   could walk about outdoors    
   without fear of being found?  If so, what would happen if they bumped into   
   someone?   
      
   Spoilers for Harry Potter and the Cursed Child:   
      
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   Late in this play, Albus Potter and Scorpius Malfoy have been brought back in   
   time to 1981 and stranded there.  They are in Godric's Hollow watching the   
   house of James and Lilly Potter.  They see James, Lilly, and Harry venturing   
   outdoors as if they    
   haven't a care in the world.  This would seem to indicate that they are   
   invisible to everyone their Secret Keeper hasn't told.   
      
   But how can Albus and Scorpius see them?  After all, the Potter's Secret   
   Keeper hasn't told them of the Potters' presence!   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)