  We perform stability analyses for discontinuous Galerkin spectral element
approximations of linear variable coefficient hyperbolic systems in three
dimensional domains with curved elements. Although high order, the precision of
the quadratures used are typically too low with respect to polynomial order
associated with their arguments, which introduces aliasing errors that can
destabilize an approximation, especially when the solution is underresolved. We
show that using a larger number of points in the volume quadrature, often
called "overintegration", can eliminate the aliasing term associated with the
volume, but introduces new aliasing errors at the surfaces that can destabilize
the solution. Increased quadrature precision on both the volume and surface
terms, on the other hand, leads to a stable approximation. The results support
the findings of Mengaldo et al. [Dealiasing techniques for high-order spectral
element methods on regular and irregular grids. Journal of Computational
Physics, 299:56 -- 81, 2015] who found that fully consistent integration was
more robust for the solution of compressible flows than the volume only
version.
