Most people are surprised when the IRS comes knocking at the door. Typically, the Revenue Officer starts asking questions and demands to enter the house. That is where the taxpayer makes crucial errors. The most important thing that the taxpayer can do is to stop the Revenue Officer and state the taxpayer is represented by a tax professional. Get a business card or write down the name, address, and telephone number of the Revenue Officer. Do not say anything other than, "my tax consultant will call you."
The Revenue Officer is trained to trick taxpayers into making damaging admissions which could hurt them in a later criminal trial. For example, one trick question is to ask a delinquent taxpayer, "didn't you know you had to file a return?". Or, "why didn't you file your tax return?". If the taxpayer answers the question it is an admission of knowledge that the return should be filed. That admission has sent many unsuspecting citizens to jail.
Another method that Revenue Officers use is to quickly get information from an unsuspecting spose or family member. For example, the Revenue Officer may ask a spouse where the taxpayer works. The Revenue Officer would then immediately prepare a wage execution to take most of the taxpayers income before it is paid by the employer. The Revenue Officer may also ask for banking information. If the unsuspecting spouse or family member reveals the name of the bank, the Revenue Officer then levies against the account, wiping out all of the funds.
The only intelligent way of handling the IRS is to not say anything. Any conversations with the government should be with your attorney present. In fact, many times it is better to have your tax attorney exclusively talk with the IRS to prevent possibly damaging admissions.