Any person who is called to provide information to the IRS, whether it be via records or oral testimony, is granted certain rights they may employ in their defense.  These rights include the Fifth Amendment Right against self-incrimination.  The Fifth Amendment grants that no one may be forced to give testimony as a witness against themselves.  It is important to note that information given voluntarily by the individual can be used to incriminate them, so the right can only be invoked to protect against an individual sharing testimony, not after the testimony has been given.

Any person who is called to provide information to the IRS is granted the right to an attorney, which includes the opportunity to hire one.  In addition to this right, any person appearing for an IRS Summons is given attorney-client privileges, or those of tax practitioner-client, wife-husband, or penitent-clergy.

Other powers granted the liable party include the right to create an audio recording of the meeting, as well as the right to ask to withhold a 3rd-party IRS Summons.  There are a number of more specific guidelines for the execution of this right, so under most circumstances, it would be advisable to seek the advice of an attorney to determine whether the exercise of this right could potentially aid the taxpayer.

Lastly, any third party summoned to the proceedings retains the right to opt not to comply with any unreasonable Summons and defend themselves from doing so accordingly.  Again, consult an attorney, whether the taxpayer under investigation or a third party, and you believe you may have been Summoned unreasonably.