In all of the cases dealing with this issue, intent had a lot to do with it. Because the taxpayers intended to demolish the building, the IRS will argue it had no value, or the taxpayers gained by the demolishion. Also, if the taxpayers require it be burned to the ground rather than letting the fire department do whatever they want with it, or put a time limit on when it must be 'used' by, it is not considered the donation of a full interest. Read the cases, and not only Scharf.
I had one of these come through audit and 1. The taxpayer had an appraisal. 2. Taxpayer had a deed transferring the structure to the F.D. 2. Taxpayer had done so 2 years earlier (by the time of the audit) and FD still hadn't done anything to the building. 4. Taxpayer had a receipt from FD. 5. Auditor was a lightweight.