I guess I still want there to be a distinction because otherwise what's to keep a leftist PAC like MoveOn.org from insisting they are a church.
Why should they be taxed for exercise of an unalienable right guaranteed under the constitution?
What does calling one's self a church have to do with it? Political Action Committe is just another case, PAC contributions should not be taxed under the 1st amendment prohibition against Congress making such law regardless of what individual citizen is contributing or the organization receiving said contribution in exercise of the freedom of speech, assembly, press or petition.
Generally, I'd say the products that come out of the system will determine what one is dealing with.
If the products of religion are faith, worship, sacrament, ritual, charity, etc., then one can look at the products of a new entity claiming to be religion and make a determination whether fraud is likely.