Tax Exemption and Silence of Court Order

The child tax dependency can mean a great deal of income to a parent.  Additionally, unless one gets to claim the child as a dependent, that parent cannot write off any daycare expenses also.  What happens when a court order is silent as to who gets to claim the children then?  The IRS guidelines say whoever the child lived with the majority of the year gets to claim the minor child as a deduction.  As such, if the court order is silent, you have to defer to the IRS guidelines.