What is the test for a judge to determine whether a parent has a right to restrict access?

In Young v. Young (1993), 1993 CanLII 34 (SCC), 49 R.F.L. (3d) 117 at 151 (S.C.C.), McLachlin J. (as she then was), stated: “...that the ultimate criterion for determining limits on access to a child is the best interests of the child. The custodial parent has no “right” to limit access. The judge must consider all factors relevant to determining what is in the child’s best interests; ... The risk of harm to the child, while not the ultimate legal test, may also be a factor to be considered. This is particularly so where the issue is the quality of access - what the access parent may say or do with the child. In such cases, it will generally be relevant to consider whether the conduct in question poses a risk of harm to the child which outweighs the benefits of a free and open relationship, which permits the child to know the access parent as he or she is.”