It is shown that if {Xt: t [set membership, variant] T} is a Gaussian process such that (T, [varrho]) is a separable metric space, where [varrho](t, s) = Cov(Xt,Xs), then, with probability 1, no sample path of X can achieve its supremum at two distinct points of T. Conversely if Pr* {supt[set membership, variant]TXt < [infinity]}>0 then (T, [varrho]) is a separable pseudometric space.