Border officials usually want to see proof that the parent travelling with the children has the consent of the other parent to take them into the country. If they're not satisfied that the parent has the other parent's permission, they may send the parent and the kids back to Canada on the very next flight. For their part, airlines often check to see whether the parent travelling with the children has permission to do so, not because this is a legal requirement but because they don't want to be stuck with bringing the parent and the kids back to Canada!

====Conditional and supervised parenting time====