If the court in Canada – Ontario made a decision about where the child has his or her habitual residence, the appeal court can intervene only if there is an obvious error in the trial decision that is determative of the outcome of the case.
The Supreme Court explained this in the case Balev (para. 38):
‘Under Canadian law, whether habitual residence is viewed as a question of fact or a question of mixed fact and law, appellate courts must defer to the application judge’s decision on a child’s habitual residence, absent palpable and overriding error. The need for deference may be inferred from the intention of the original states parties and the decision not to define habitual residence in the body of the Hague Convention. The goal was to avoid legal technicalities and to adopt a fact-based determination.’
In the case H.L. v. Canada, 2005 SCC 25, (2005) 1 S.C.R. 401, at para. 110, it was explained:
‘A palpable and overriding error is one that is clearly wrong, unreasonable, or not reasonably supported on the evidence.’
In the case Salomon v. Matte-Thompson, 2019 SCC 14, 432 D.L.R. (4th) 1, at para. 33, the Supreme Court explained:
‘(w)here the deferential standard of palpable and overriding error applies, an appellate court can intervene only if there is an obvious error in the trial decision that is determinative of the outcome of the case.’