Close-in exoplanet-exomoon systems (a < 0.05 AU) naturally experience extreme tidal forces due to the proximity of the stellar gravitational tide, driving runaway melting and volcanism at >> 1000x the observed rate of volcanic escape at Jupiter’s moon Io. Volcanic volatiles discerned in close-in gas giant exospheres have yet to be directly associated with the period of a third body. Nonetheless, the extremely bright resonant scattering of the neutral sodium doublet Na D2/D1 (~350x photon flux of Lyman-alpha) continues to indicate several "exo-Io" candidates, consistent with observed alkali absorption line profiles during and near planetary transit. We outline how this phenomenon may manifest in current and future infrared spectra at candidate volcanic exoplanet systems. Lastly, we present time-dependent radiative transfer simulations of an evaporating exomoon candidate: WASP-49 b I in sodium light. Depending on the satellite phase angle, diurnal tides and thermal outgassing rates imply that transient or variable gas signatures of volcanic gas (e.g., Na/K, SO2) are rather expected at exoplanet systems possessing a primordial or captured exomoon.