There's a difference though between distributing an installable packaged hack (that would have to have pirated Apple files in it), and posting a "how-to" for those that have access to a 4S and are willing to take the potential legal risk. Say for example, that I own a 4S and a 4, and I want them BOTH to be able to run Siri. There's still a theft of service argument, but it gets much much fuzzier. I don't see any reason why they couldn't publish a how-to that was "for educational purposes only" that cautioned people to "proceed at their own risk".