I haven't read this whole thread, but I just thought I'd add this idea: I have a friend who carries post-it notes with her. When she finds a book like that, instead of hiding it or buying it to burn or whatever, she writes a note and sticks it inside. She recommends other options depending what the book is: the No-Cry Sleep Solution, Gentle Discipline, etc., for Baby Wise, The Thinking Woman's Guide to Birth for mainstream pregnancy/birth books, etc. That way someone can still buy the "bad" book if they want, but maybe they've been given another possible resource that they otherwise would never have known about.
Sometimes when I'm in a bookstore, if there are enough copies of a book I like, I'll stick one in front of Babywise or some other awful book. That way, Babywise is still there, where people can find it, they just have to move another alternative out of the way to find it. Again, maybe they didn't know there were other options out there and maybe someone will consider reading Sears instead.
I think it's more important that people be exposed to other ideas so that they can make informed decisions. If you don't know any better and your MIL and best friends and ped are all telling you that you NEED to follow Babywise, why wouldn't you? But if you read that AND some more gentle resources, you might be more likely to not blindly follow the Babywise advice. Sadly, I think a lot of people just don't know what else is out there.