If the IRS is going to challenge what you filed as your proper tax return, you will receive notification in writing. It will clearly spell out the issues. It is up to the taxpayer at that point to prove why the 1099 was treated which ever way it was when the return was filed. Similar issue to paying sales tax in AR on stuff bought online. As a resident here, you are, by law, supposed to report the items you purchased that did not have sales tax withheld at the time of purchase. I have never heard of anybody being clipped on this but the law is there as is the place to report on the return. Best bet for most folks is engage with a tax professional for tax filings and let them deal with the IRS or State agency if applicable when and if they come calling. Taxpayers 99.9% will just fornicate them selves trying to represent themselves before the IRS.