In the IRS publication "Know Your Rights As a Taxpayer" it explicitly states that taxpayers have the right to pay only what is legally due, and to have the IRS apply all tax payments properly. As such, they are not after you for more money than you owe.
According to Eric J. Nisall, a South Florida- based accountant who specializes in helping freelancers and small businesses, in some instances, the IRS may actually find deductions that were missed and could have been taken.
If you are wondering whether or not this rule about paying only what is due is enforced, in 1998, Congress passed the Internal Revenue Service Restructure and Reform Act (aka the "Taxpayer Bill of Rights") as a means of making sure the IRS treated taxpayers fairly [source:U.S. Government Printing Office] . Among its many provisions, the IRS can't seize someone's personal home to satisfy a liability of $5,000 or less.