Anti-obscenity precedents (if they exist) are useless against Hannity and Limbaugh.
Ultimately, you need to remember that Stern's move is VOLUNTARY.
No do you really think they wouldn't try to hit stations that broadcast Limbaugh and Hannity with fines whenever he could?
Take a look at the site and you tell me if a Kerry Administration FCC (or worse yet, a Hillary Administration FCC) wouldn't be able to make an obscenity precedent stick if enough complaints from a trumped-up campaign by Media Matters?
http://mediamatters.org/archives/search.html?topic=The%20Rush%20Limbaugh%20Show
Anyone can file an FCC complaint. Remember how Oprah was targeted by Howard Stern for HER show's sex talk that *didn't* get fined? And oh, yeah, isn't legislation in the works to INCREASE the maximum fine the FCC can impose?