We consider finitely generated shift-invariant spaces (SIS) with additional
invariance in $L^2(\R^d)$. We prove that if the generators and their translates form a
frame, then they must satisfy some stringent restrictions on their behavior at infinity.
Part of this work (non-trivially) generalizes recent results obtained in the special case
of a principal shift-invariant spaces in $L^2(\R)$ whose generator and its translates form
a Riesz basis.