not filing return when no tax due
Michael's right: the penalties for late or non-filing are based on the amount due, so no amount due, no penalty. (The IRS once imposed a $100 minimum penalty on a return over 60 days late, but lost in Tax Court since the person owed no tax.) But Michael 's also right that if you don't file, for whatever reason, you'll likely get a letter from the IRS asking why.
Technically, whether you're "required" to file usually is based on only four factors: marital status, filing status, age, and gross income (see, e.g., pages 5-8 of IRS Publication 17.) Again, these rules have no teeth if you don't owe. However, for practical reasons I advise all my clients to file every year.
I'm not a CPA but I have an LL.M. in tax and a good amount of experience. The poster's point really merits a long discussion, but here are a few reactions:
1. When someone doesn't owe tax he or she is almost always owed a refund, and the only way to get it is to file (wait too long and you can forfeit the refund.)
2. You may owe nothing because of deductions the IRS won't see unless you put them on a return. I had a case where a nonfiler got a big bill when the IRS filled out a return for him that made every assumption against him. That changed when we filed using his actual records.
3. If you don't meet the IRS minimum filing requirements mentioned above, filing anyway gets that fact on record and starts the normal 3-year statute of limitations (there is none without filing.) There is also a special IRS program targeting habitual nonfilers, and it's good not to even start down that road.
4. Your return may be completely straightforward and bulletproof, but I'd still crunch the numbers with thorough software just to be sure not to miss other taxes payable on the 1040 (even the AMT is affecting more people each year) or other credits (besides your withheld taxes), which may increase your refund substantially.
5. You may also have to deal with state and maybe local taxes. A common pattern for New York City residents is to get a Federal refund but owe a smaller amount on the NY state/city return.
6. Some returns and tax records should be completed and kept so you don't overpay later. Capital loss carryovers, obviously, but also things like Form 8606 for IRA's, and the cost of improvements on property you may own a long time, such as your residence (there are great tax breaks when you eventually sell).
Other tax contribuors can surely add a lot to this discussion. I just think that people really should crunch the tax numbers every year, and once that's done they might as well file and avoid potential headaches.