"Red Flag" is a favorite term of journalists who write stories about alpaca farms one day and tax returns the next.  Did you know the original "red flags" were those attached to returns of IRS employees, to make sure they were all audited?  There are no little men with green eyeshades looking at tax returns to spot OIH deductions, so that red flags can be attached to them.  Red flags are an urban tax myth.  Always good for a cheap headline, though.