Actually the Offical TV Guide mentioned it. Talking about the episode airing yesterday they said "A news report about the end of the world brings out King Of The Hill's Hank and the Smiths From American Dad" and, for some reason, Anne Hathaway". So obviously it wasn't the internet that was the only place the joke/rumor was leaked to.
Agreeded that the blame shouldn't just be put against Seth. Then again much more then say Matt Groening (who you really have to wonder just what he does for The Simspons nowadays) Seth has to be involved with most every aspect of FG/AD or even The Cleveland show, since they are all projects he started or helped start and owns the rights to them, as well as how he still voices a lot in every episode and thus at the very least, has to APPROVE Of all the jokes that go into every story. So obviously even if he didn't write this scene or that scene, he's okay with it and thinks it's funny and shouldn't be changed to be in his show. Which may not mean he writes it but it means he should be associated with each and every episode in at least that fashion.
As for the actual episode, the only really funny part about it were Peter's attempts to get out of Jury Duty (including his hatred of Ants, and running in the hallway against the Judge's orders) and everyone finding out about the world ending and they're reactions (I really think Herbert should of just knocked out Chris and taken him but his scene was funny, and Quagmire's scene would of been funny if Joe had pummeled the crap out of him afterward for sleeping with Bonnie) but yeah the whole third act being Peter trying to spend time with the kids... didn't really work for me. I mean there is reasoning behind it (since it obviously seems like in previous eps it looks like he dosen't care for Chris and Stewie, and we know he usually never cares about Meg. I did like Meg actually leading the others in a way to ignore Peter and them all ignoring him) but it just felt so disjointed. Like "how can we fill out the rest of this epsiode after the prank? Oh let's have Peter spend time with the kids, since even we know him having a last minute recollection with Lois would be terribly old shictk" which really shouldn't be done in the third act (if any act of the show). The whole third act should of everyone in town getting revenge against the news station really, though glad to see them make a more modern video game refrence at the end. (A VERY rare sight on this show).