But my thought was that if a lust based WCV can shut down the inhibitions of a person, then maybe a gluttony WCV could shut down the gag reflex or something similar. It's like a WCV owning a strip/night club. They feed off the latent sexual atmosphere, but that doesn't fully sate them, so a few customers (that wouldn't be missed) would "disappear" from time to time. It has been scientifically been proven that having a food craving sets off the same parts of the brain as a drug addiction, just to lesser degrees. Chocolate Sets off the same part of the brain as sex does. There is more to food then just a need for calories.
If you want to argue a group emotion versus solitary state of mind. Despair resulted in suicide in the books. That can be considered one of the most greedy, most solitary escape method out there. There is no interaction from the vampire or other people like a lust based WCV, except for the manipulation of the mind. They then feed of of the process, and then the death. This is what I was basing the whole idea on.