  We discuss necessary conditions for a network of cosmic domain walls to have
a chance of providing the dark energy that might explain the recent
acceleration of the universe. We derive a strong bound on the curvature of the
walls, which shows that viable candidate networks must be fine-tuned and
non-standard. We also discuss various requirements that any stable lattice of
frustrated walls must obey. We conjecture that, even though one can build (by
hand) lattices that would be stable, no such lattices will ever come out of
realistic domain wall forming cosmological phase transitions. We provide some
simple numerical simulations that illustrate our results and correct some
misconceptions in the published literature, but a detailed numerical analysis
is left for a companion paper.
