Considering the halide ions as a series that ranges from kosmotropic to chaotropic , or equivalently whose surface activities decrease in the order I -> Br -> Cl - F -, it has previously been noted that no single mechanistic explanation for this ordering can be gleaned from atomistic simulations . Changes in the water-water interactions as the an ion approaches the interface appear to play a role . The present analysis, based on accurate quantum-mechanical calculations of ion-water interaction energies, supports the notion that ion-water interactions alone do not readily afford any kind of a diagnostic (let alone a mechanism) to determine whether an ion resides in a bulk or interfacial environment. This null result complements our recent conclusion that short-range (firstshell) solvation structure is extremely similar in the bulk and interfacial environments . The detailed mechanism of soft anion surface activity remains an open question.