  It has been argued in hep-ph/0212382 that there may be observable effects
from photon triple splitting in an extended version of quantum electrodynamics
with Lorentz violation in the fermion sector. The argument is based on an
analogy with photon splitting via collinear parametric down-conversion in
optically active crystals. In this Comment, we point out that the analogy is
misleading and that, at the order considered, the probability of on-shell
photon triple splitting is strictly zero.
