Since this has veered into a discussion on audits, I want to share my experience FWIW. I believe people should feel free to take any deductions or credits they are entitled too without fear of being audited. Obviously the deduction should be defensible and documented.
I've been on the receiveing end of IRS audits as an individual and as the ranking officer of a tax exempt corporation. They are anxiety producing pains in the a**. Lots of work pulling together documentation and generating financial statements. But in all three of my experiences the IRS employees were helpful and polite. Perhaps it was because my audits were random and I was not being investigating for fraud. But in my case there was clearly no animosity. When they identified a deduction they felt I wasn't entitled to, they corrected my taxes and I had to pay the owed tax plus interest, but they didn't apply penalties. Since they were amending my return they even allowed me to increase my allowable deductions (some of which I hadn't initially taken hoping to avoid audit red flags). The only thing that was frustraing was when they requested some very complicated reports during the interview with no notice. When I called that out, they admited that they don't provide notice, because they want to see what the reports look like without the auditee having time to amend them.
I hope I don't ever have to go through one again, but it wasn't so painful that I'd avoid taking deductions I'm entitled too. That includes legitimate business or volunteer expenses.