That's slightly short-sighted, I think. The MM has a rather non-film-like spectral response that is typical of monochrome CCD sensors. It's not really optimized for optimal aesthetic rendering in pictorial photography but rather for reasonable* quantum efficiency in the visual range, being adapted (as it is) from sensor designs that were rather clearly intended for scientific applications.
I can't imagine having one of those and not using color filters with it.
*The KAF sensors have not had leading-edge sensitivity or noise characteristics for at least a dozen years, and among CCDs were trumped by Sony's superior interline CCDs at least that long ago. I know this because 12-15 years ago is when serious microscopists -- who almost universally use monochrome sensors -- began our mass exodus from Kodak to the markedly superior Sony sensors. Not only can't I imagine shooting a KAF without a color filter, I can't imagine laying out that kind of coin for sensor tech that's that far out of date. Now most of us are using EM-CCDs cooled to -80, or large-array sCMOS, or we're still sticking with those superior Sony-based CCD
cameras.