Despite the U.S. Department of State's claim that U.S. consulates and embassies have been instructed to annotate applicants' TN visa stamps with this 3-year notation, I am still seeing TN visa stamps being issued without this notation.
For example, a recent applicant who applied for a TN visa at the Nuevo Laredo U.S. Consulate was issued a TN visa stamp without this notation even though his employer specifically requested that the visa be annotated in this manner. I am certain that the lack of this notation contributed to the issuance of a 1-year I-94 card at the border by USCBP. The issuance of this I-94 was also in disregard to the employer's request for a 3-year I-94 card.
The end result? This individual will now need to obtain a new I-94 card within a 1-year period instead of having the authorization to reside and work in the U.S. for the 3-year period authorized under TN visa status, and specifically requested by his employer.