We establish conditions under which the universal and reduced norms coincide
for a Fell bundle over a groupoid. Specifically, we prove that the full and
reduced C*-algebras of any Fell bundle over a measurewise amenable groupoid
coincide, and also that for a groupoid G whose orbit space is T_0, the full and
reduced algebras of a Fell bundle over G coincide if the full and reduced
algebras of the restriction of the bundle to each isotropy group coincide.Comment: 13 page