Deception succeeds more easily among strangers than friends. [causal]
Passing is the most encompassing of the identity games. Not only the strangers one encounters in public are deceived but one's friends and acquaintances, as well. It is also the most risky. There is always the chance that friends and acquaintances will spot inconsistencies and guess the "truth" or that someone who "knew one when" will show up and "blow one's cover." … Because this is such a familiar phenomenon, I shall not consider it further, except to point out that it is a game far more easily played in public space amidst strangers than in private space amidst friends. As with all sorts of deception, the less information available to others, the greater the chance for success.
Lyn H. Lofland, World of Strangers_ Order a…, loc. 947