Can I omit my undergraduate school from my CV?
There are all sorts of CVs, ranging from complete CVs to abbreviated highlights.  Job applications or promotion/tenure cases generally require complete CVs, but shorter versions can be useful for getting a quick overview in other circumstances.  Senior faculty sometimes post short CVs on the web, to emphasize their best qualities (most famous papers, most prestigious prizes, etc.).  For comparison, a complete CV could easily be twenty pages or more, which would be much more cumbersome.  I would not recommend imitating this until your CV also becomes unmanageably long; otherwise, it can come across like unrealistic boasting: "there are so many wonderful things I could tell you about myself that I wouldn't want to waste time on trivia like where I went to college."  Of course it can sound like boasting for senior faculty as well, but so can posting a lengthy but complete CV ("I bet the world is eager to read a list of every invited lecture I've given"), so there's no really modest option there.