Polarizability may also be particularly important for these systems due to the water model. Particularly, with fixed-charge force fields, the water model is also non-polarizable, which may be an especially bad approximation for systems like these where water interactions with a buried hydrophobic cavity are at play . The expectation is that binding in host-guest systems like those examined here are heavily influenced by the hydrophobic effect, and the hydrophobic effect will certainly be strongly influenced by properties like polarizability.