Under the assumption that a UV theory does not display superluminal behavior,
we ask what constraints on superluminality are satisfied in the effective field
theory (EFT). We study two examples of effective theories: quantum
electrodynamics (QED) coupled to gravity after the electron is integrated out,
and the flat-space galileon. The first is realized in nature, the second is
more speculative, but they both exhibit apparent superluminality around
non-trivial backgrounds. In the QED case, we attempt, and fail, to find
backgrounds for which the superluminal signal advance can be made larger than
the putative resolving power of the EFT. In contrast, in the galileon case it
is easy to find such backgrounds, indicating that if the UV completion of the
galileon is (sub)luminal, quantum corrections must become important at distance
scales of order the Vainshtein radius of the background configuration, much
larger than the naive EFT strong coupling distance scale. Such corrections
would be reminiscent of the non-perturbative Schwarzschild scale quantum
effects that are expected to resolve the black hole information problem.
Finally, a byproduct of our analysis is a calculation of how perturbative
quantum effects alter charged Reissner-Nordstrom black holes.