  In this complementary note to [1] (arXiv:1501.05641), we provide an
alternative proof for the factorial decay estimate of iterated integrals for
geometric rough paths without using the neoclassical inequality. This note
intends to aid the readers on the proof in [1] which works also for branched
rough paths. Just as in [1], the proof here is an extension of Lyons 94' [4]
from Young's integration to geometric rough paths.
