From the second paragraph: "The preloading will occur in cases when the top match generated by the omnibox's autocompletion functionality is a site that the user visits frequently"

Since you probably don't "frequently" visit malware-filled websites, this shouldn't be an issue - although I wonder if Chrome would load it anyway or not.. It seems to do a better job than most browsers of pre-emptively warning you when you try to visit a dangerous website, at least in my experience.