There are some occassions when a delay in returning children is inevitable.  However, on rare occassions there can be a genuine concern over whether the child will be returned.  For instance the other person may have indicated an intention to remove the child and this has been backed up by actions they have taken such as asking for the child's passports etc.  If there is a genuine concern over a child not being returned from contact or being removed from the Country without your consent then emergency measures may have to be taken.