The relationship between corporate technology platforms and the open-source communities that sustain them has become increasingly exploitative. This paper documents a systematic pattern of feature copying from independently developed open-source projects into commercial products offered by GitHub, Microsoft, and Visual Studio Code. Through a longitudinal case study spanning June-July 2026, we catalog 40+ instances where product decisions, feature implementations, and user-interface improvements in these platforms appear to have been directly inspired by-or copied from-public repositories maintained by a single open-source developer. We argue that this pattern represents a form of institutionalized idea theft that undermines the sustainability of open-source innovation and raises serious ethical and legal questions about the corporate stewardship of platforms that depend on free community labor. We conclude with recommendations for policy reforms, including mandatory attribution, reciprocity mechanisms, and independent oversight of corporate open-source engagement.