Heh. Well in this case I have only personal experience to draw upon. It did make a good impression on the other fellow who did decide at that point that there was something else more urgent for him to be doing.I think your line "From the view of your potential assailant, however, seeing a smooth butterfly knife draw can be intimidating" is loaded with mystique.
To CDRGlock: Sure they can be opened quickly. But not "just as fast." Why bother trying to make the case? Nobody has ever suggested that you get a butterfly knife because of speed of deployment.