This paper establishes a behavioral-forensic framework to analyze non-willful non-compliance among high-net-worth (HNW) dual-citizenship individuals and enterprise operators navigating the U.S.-Mexico financial corridor. Despite the passage of the Foreign Account Tax Compliance Act (FATCA) and the bilateral Model 1 Intergovernmental Agreement (IGA), taxpayers routinely exhibit psychological paralysis regarding automated transparency. This research deconstructs four reinforcing cognitive failure modes: Optimism Bias, Hyperbolic Discounting, Cultural Dissonance, and "Algorithmic Deference". By introducing the Systemic Intent Shadow (SIS) model, this paper formalizes the operational disconnect between Upstream Architectural Intent and Downstream Operational Gatekeeping...