IRS Scrutiny of Gift and Estate Tax Returns
The IRS will scrutinize gift tax returns and estate tax returns because there is much more "wiggle" room than income returns. The process also invites more creativity by taxpayers and their attorneys. Here is the IRS manual on gift and estate tax returns.
Preparing such returns should be done with the assistance of professionals. This is especially true for exectutors, trustees, and personal representatives of an estate, who could be personally responsible.