(petitioners were two children of 1994 decedent and were beneficiaries of residuary testamentary trust that received most of decedent’s estate, including 13/16 interest in cattle ranch; ranch value reported on estate tax return at substantially below FMV in accordance with I.R.C. Sec. 2032A; petitioners signed consent agreement (one via guardian ad litem) agreeing to personal liability for any additional taxes imposed as result of sale of elected property or cessation of qualified use; IRS disputed reported value but matter settled; years later, trust sold easement on ranch restricting development; gain on sale of easement reported with reference to Sec. 2032A value and K-1s issued showing proceeds had been distributed to beneficiaries; beneficiaries did not report gain as reflected on K-1s and then asserted that ranch undervalued on estate tax return and that gain reportable should be reduced by using FMV tax basis; court determined that Sec. 2032A value pegs basis via I.R.C. Sec. 1014(a)(3); court upheld consent agreement; accuracy-related penalty imposed because advice sought only after petitioners failed to report any gain).