Notwithstanding half a dozen theoretical publications, well-converged density-functional calculations, whether based on a local-density or generalized-gradient exchange-correlation potential, whether all-electron or employing pseudopotentials, underestimate CO's preference for low-coordination binding sites on Pt(111) and vicinals to it. For example, they imply that CO should prefer hollow- to atop-site adsorption on Pt(111), in apparent contradiction to a host of low-temperature experimental studies.