IANAL, but I think you're trying to say that if this person writes it down in a journal, or a blog, that this person will not be able to stop someone from patenting it.
If that's what you're asserting, then you're wrong. There's a court case about prior art, which ruled something to the effect that prior art is anything that is accessible by the public (i.e. a PhD dissertation available through a public university library only needs to be available for access, and you do not need to prove that someone actually looked at it or read it after it's been cataloged). Once an examiner finds a reference with a varifiable date that predates a filing by one year, then 35 USC 102(b) is used and it creates a bar for patenting (e.g. the person seeking a patent cannot swear back and come up with evidence that they in fact invented more than one year ago).
In the end, I'm almost positive that blogs can be used as evidence, especially if they provide enough detail and motivation to do something. It might even be best to let archive.org to archive your blog, so that the dates have a second varifiable date attached to it.
Now, if all you meant to address, was that a person cannot get a patent after abandoning, suppressing, or concealing the subject matter, then that is correct. But, I haven't heard of many 102(g)(2) rejections.