Several of my electronic platforms have similar language under the 'Terms of Use'. As to the actual subject of the ZH post, what is described in the letter is most definitely NOT front-running and ZH should know this. If you want a detailed explanation, see here: http://fridayinvegas.blogspot.com/2010/01/talking-your-book-vs-frontrunning.html
Goldman's email is just a friendly LEGAL reminder to all clients using their "Trading Ideas" that they MIGHT BE treated worse than their top-notch clients. Nothing more and nothing less. Yawn.