"for an income discrepancy of less than $1,000?"

Unless $750 is the only money they made, and the only 1099, how would the IRS even know they under-reported? If you report your business revenue, and then you get no 1099, you still need to report the business revenue. If you report $500 and the IRS gets notification you made $750, they still don't do document matching, and they don't know if your $500 is your net and you didn't report gross.

This might be much ado about nothing.