It has been shown that classical non-minimally coupled scalar fields can
violate all of the standard energy conditions in general relativity. Violations
of the null and averaged null energy conditions obtainable with such fields
have been suggested as possible exotic matter candidates required for the
maintenance of traversable wormholes. In this paper, we explore the possibility
that if such fields exist, they might be used to produce large negative energy
fluxes and macroscopic violations of the generalized second law (GSL) of
thermodynamics. We find that it appears to be very easy to produce large
magnitude negative energy fluxes in flat spacetime. However we also find,
somewhat surprisingly, that these same types of fluxes injected into a black
hole do {\it not} produce violations of the GSL. This is true even in cases
where the flux results in a decrease in the area of the horizon. We demonstrate
that two effects are responsible for the rescue of the GSL: the acausal
behavior of the horizon and the modification of the usual black hole entropy
formula by an additional term which depends on the scalar field.Comment: 25 pages, 2 figures; paper substantially rewritten, major changes in
the conclusion
