Others claim to be trapped into non-filing status because of past decisions.

FORBES: Non-Filers Beware: Who's That Knocking at Your Door ?

Indeed, as I have written here, while the government loses hundreds of billions of dollars in revenues due to underreporting, non-filing and underpayment each year, the IRS simply lacks the resources to enforce the Code.

FORBES: The Fiscal Cliff And A Call For A Simpler Internal Revenue Code

Tax non-filing and underreporting were also up.

FORBES: New IRS Tax Gap Report: Cheating Still Rampant

If you are an American Canadian and have not reported to the IRS that you have an RRSP (similar to an IRA in the US), you owe Uncle Sam a non-filing penalty of 25% of the value of the account.

FORBES: Handling New IRS Foreign Reporting Requirements Without Doing Jail Time

The requirement to file an annual return would not seem to be one of the more iffy provisions in the Tax Code, especially since Snipes made millions of dollars during each of the three years of non-filing for which he was convicted.

FORBES: In Defense of Wesley Snipes (Really)

Filing non-resident U.S. tax returns, Goosen allocated 50% of his endorsement fees and bonuses from Acushnet, TaylorMade and Izod to personal services, classifying the other 50% as royalty income.

FORBES: IRS Sand Trap For Pro Golfers

Filing a claim with a non-life insurer can be a nightmare.

ECONOMIST: Premium market

That included a 4 percent declined in carbonated soft drinks and a 3 percent decline in non-carbonated drinks, according to a regulatory filing with the Securities and Exchange Commission.

WSJ: Pepsi rolls out a new shape for bottle

In its previous 10-Q filing Citi mentioned it was receiving inquiries from non-U.S. authorities but did no specify which ones.

FORBES: Libor Problems Go Global, Singapore Authorties Probe Citi Over Rigging