Deferred income tax liabilities arise because of differences in the policies used to account for revenue and expenses for financial reporting purposes versus the policies utilized to report revenue and expenses for income tax purposes. For instance, revenue might be recognized for financial reporting purposes at the point of sale, whereas for income tax purposes, revenue might be recognized at the point of cash collection using the installment method. It is generally accepted practice to discount liabilities to their present value for purposes of presentation on the balance sheet. Discuss why deferred income tax liabilities are not valued on corporate balance sheets at their present value.