  We examine the effect of Galactic diffractive interstellar scintillation as a
means of explaining the reported deficit of Fast Radio Burst (FRB) detections
at low Galactic latitude. We model the unknown underlying FRB flux density
distribution as a power law with a rate scaling as $S_\nu^{-5/2+\delta}$ and
account for the fact that the FRBs are detected at unknown positions within the
telescope beam. We find that the event rate of FRBs located off the Galactic
plane may be enhanced by a factor ~30-300% relative to objects near the
Galactic plane without necessarily affecting the slope of the distribution. For
FRBs whose flux densities are subject to relatively weak diffractive
scintillation, as is typical for events detected at high Galactic latitudes, we
demonstrate that an effect associated with Eddington bias is responsible for
the enhancement. The magnitude of the enhancement increases with the steepness
of the underlying flux density distribution, so that existing limits on the
disparity in event rates between high and low Galactic latitudes suggest that
the FRB population has a steep differential flux density distribution, scaling
as $S_\nu^{-3.5}$ or steeper. Existing estimates of the event rate in the flux
density range probed by the High Time Resolution Universe (HTRU) survey
overestimate the true rate by a factor of ~3.
