Are you really saying that you don't trust it, or that your gpg tool tells you that you don't trust it?
Because I suspect that in reality you do trust it, at least a little bit. And if I had had the forethought to sign my previous correspondence with you, you would probably trust it a lot more, despite what gpg tells you.
I've been trying to think of non-digital analogies and the idea of "Public Notices" comes fairly close. There are cases were placing a public notice and not getting a response in some reasonable time period means that you can proceed on the assumption that no-one else has an interest in the issue (handling deceased estate is one example I think).
So my original post is like a public notice. If it was faked, you can be pretty sure that the real neilbrown would have found a way to complain. He hasn't yet. Give it time, but if you don't hear anything in a couple of weeks, you can probably increase your trust level substantially.
[alright, I admit it - I just don't like parties and want to find a way to get my access to kernel.org back without having to go to a key-signing party :-) ]