liar’s affidavit
n.— «It also creates a presumptive value for sales taxes on used cars based on the “blue book” sale price. (This is a tax change often known as “Liar’s Affidavit” around the Capitol.)» —“Perry, Sharp unveil revised franchise tax plan” by William Lutz East Texas Review (Longview, Texas) Apr. 6, 2006. (source: Double-Tongued Dictionary)