Joseph,
The fraternity may have a “sincerely held religious belief” in being allowed to serve alcohol to minors without any consequences. And the adult serving alcohol to minors on Purim may not be completely consistent in his observance of Judaism. Really I don’t think either of us want the courts to start examining our religious observance.
Actually I gave this as an extreme example. The religious exemption to social hosts laws, as described by Chuck Schwab, is big enough to drive a Budweiser truck through. Also, as I’ve mentioned above, it’s not consistent with other areas of law, which don’t allow religious exemptions for neglect/ abuse. I’m not discounting Mr. Schwab’s experience, but I think that just because this type of crime has never been prosecuted doesn’t mean it never will be prosecuted. As illini07 noted, not all social host laws have religious exemptions, and probably neither do all teen party laws (which have a lower threshold for prosecution in that adults can be held liable even if no crime results).