What is the test for using the "grave risk" defense?

Because of the strong presumption that children should be returned to the place of their "habitual residence," we interpret the grave risk defense narrowly. Blondin v. Dubois, 189 F.3d 240, 245-46 (2d Cir. 1999) ("Blondin I"). As we have observed elsewhere, an overly permissive acceptance of the affirmative defense "would lead to the collapse of the whole structure of the Convention by depriving it of the spirit of mutual confidence which is its inspiration." Id. at 246 (citation omitted). The respondent bears the burden of establishing the applicability of the "grave risk" defense by clear and convincing evidence. See 22 U.S.C. 9003(e)(2)(A).