Camp Fema Debtors Prison?

Somebody that I know very well showed me a letter received from the IRS that was somewhat scary to me when you think about the implications of it. This person defaulted on a credit card in the late 1990's due to a divorce. It was ordered that both parties pay their part of the debt which was figured out civilly by both of them. My friend paid but did not know that the other did not.

To get to the point: The bank apparently just wrote the debt off in 2011 and the letter received from the IRS stated that my friend owes $600.00 because the credit was not reported in that tax year as income.

I never heard of this before now and wonder how many people have or will be receiving these letters of enforcement. This is a crafty way to have debtor prison without knowing that is what is happening. Owing the IRS is much different than owing a bank and Ive seen so many reports about loan and credit defaults that this made me think that the fema camps were built for this reason. The letter stated under the (what is this?) category that it was a credit default or foreclosure that was not reported as income. Pay attention if you have defaulted in that several years because this is real