Why claim a rental property on your tax return if your AGI is too high to receive the deduction.

Are you referring to the special allowance for active participation (maximum of $25,000)?

You are required to report income/expenses on Schedule E for rental real estate. 

Typically, once your rental expenses and depreciation get your taxable rental income to zero (usually every year) any additional loss is "carried over" to the next year. So with each passing year your Passive Activity Loss (PAL) carryover will continue to grow.

You will be able to realize and actually take those losses in the tax year you sell the property, not only against rental income and your gain on the sale, but also against other ordinary income. So your PAL carry overs are not lost forever.

However, if you don't claim the loss in the tax year it occurs, then you can't "take" the loss in the tax year you sell the property.

think of what happens if you don't report these losses each year and at some date in the future you sell.  those disallowed losses become allowed but if you don't report them every year you may be out of luck in trying to claim them. also if held long enough there may be rental income in the future which could be offset by the carryforward losses. but again not if you don't report them.  I'm sure the US Treasury would appreciate the income tax contribution you would be making.