  It is now a firmly established fact that all family lepton numbers are
violated in Nature. In this paper we discuss the implications of this
observation for future searches for rare tau decays in the supersymmetric
see-saw model. Using the two loop renormalization group evolution of the soft
terms and the Yukawa couplings we show that there exists a lower bound on the
rate of the rare process mu --> e gamma of the form BR(mu --> e gamma) > C
BR(tau --> mu gamma) BR(tau --> e gamma), where C is a constant that depends on
supersymmetric parameters. Our only assumption is the absence of cancellations
among the high-energy see-saw parameters. We also discuss the implications of
this bound for future searches for rare tau decays. In particular, for large
regions of the mSUGRA parameter space, we show that present B-factories could
discover either tau --> mu gamma or tau --> e gamma, but not both.
