http://law.justia.com/cases/new-york/court-of-appeals/1974/35-n-y-2d-92-0.html
Thus, in our view, to succeed in establishing the taxable status of real property owned by Watchtower Bible and Tract Society of New York, Inc., under these provisions the taxing authority must prove not only that the corporate owner is organized exclusively for bible and tract purposes, but as well that it is not organized or conducted exclusively for religious purposes. It is on the latter branch of this requirement of proof that we conclude the taxing authorities have failed in this instance...The religious activity of Jehovah's Witnesses consists in major part of house-to-house preaching, an integral part of which is the attendant distribution of religious literature, the bible and religious books, magazines and booklets, all produced and published by the society. The great weight of judicial authority has uniformly held that the preaching activity of Jehovah's Witnesses from house to house is done as ministers of the gospel and it is held that it is religious preaching...We accordingly conclude that the respondent society is organized and conducted exclusively for religious purposes within the meaning of the statute and therefore is not subject to taxation...There is an interesting bit after that about the fact that wts had rent-paying tenants. The court seems to be saying they weren't asked to rule on partial exemption, so they cannot.