  The formalism underlying the analysis of e+e- -> pi+pi- in the rho-omega
interference region is carefully revisited. We show that the standard neglect
of the pure I=0 omega, omega_I, `direct'' coupling to pi-pi is not valid, and
extract those combinations of the direct coupling and \rho-omega mixing allowed
by experiment. The latter is shown to be only very weakly constrained by
experiment, and we conclude that data from the e+e- -> pi+pi- interference
region cannot be used to fix the value of rho-omega mixing in a
model-independent way unless the errors on the experimental phase can be
significantly reduced. Certain other modifications of the usual formalism
necessitated by the unavoidable momentum-dependence of rho-omega mixing are
also discussed.
