I spent the Fourth of July in WV with Appalachia Service Project making homes warmer, safer, and drier. It was very ASP appropriate that we watched the fireworks that were in the Walmart parking lot from the Lowe's parking lot, the two places we shopped the most, and probably the two largest employers in Nicholas County.
I would, in most cases, state that the taxpayer is the one that determines what is ordinary and necessary for his business. After all it is his business and his tax return. If the expense is material and questionable the taxpayer should be advised by the preparer and if the taxpayer insist on deductible then preparer should withdraw from the preparation.