The most common red flag for IRS auditing (behind home office deductions) is charitable giving. The IRS keeps stats on the average charity to income ratios. Anyone who gives excessively in relation to their income (what we would deem a true giver) is at greater risk of being audited. Consumers know this and must waste time and energy proving that they did in fact give to charity in such a quantity. Many hedge against this risk by contributing less as a function of their income. Thus, the IRS not only decreases charity by taxation they decrease charity by the threat of auditing. Go IRS!