  The guarantees of security and privacy defenses are often strengthened by
relaxing the assumptions made about attackers or the context in which defenses
are deployed. Such relaxations can be a highly worthwhile topic of
exploration---even though they typically entail assuming a weaker, less
powerful adversary---because there may indeed be great variability in both
attackers' powers and their context.
  However, no weakening or contextual discounting of attackers' power is
assumed for what some have called "relaxed definitions" in the analysis of
differential-privacy guarantees. Instead, the definitions so named are the
basis of refinements and more advanced analyses of the worst-case implications
of attackers---without any change assumed in attackers' powers.
  Because they more precisely bound the worst-case privacy loss, these improved
analyses can greatly strengthen the differential-privacy upper-bound
guarantees---sometimes lowering the differential-privacy epsilon by
orders-of-magnitude. As such, to the casual eye, these analyses may appear to
imply a reduced privacy loss. This is a false perception: the privacy loss of
any concrete mechanism cannot change with the choice of a worst-case-loss
upper-bound analysis technique. Practitioners must be careful not to equate
real-world privacy with differential-privacy epsilon values, at least not
without full consideration of the context.
