The point of using incognito is to be unauthenticated. Otherwise, wouldn't the post always be visible to the submitter, regardless of whether or not it is in the spam filter?
This would only be effective if you know that a leak is going to occur. Otherwise, this wouldn't mitigate any specific leak as it is unknown when the leak would occur.
However, a strategy that could worsen the effectiveness of Wikileaks would be to constantly spam them with large amounts of plausibly authentic fake documents. Maybe I'm missing something but this seems like such an easy way to tie up the resources of Wikileaks that you'd have to wonder why these governments and corporations aren't already doing this.
Ok, so demos are great to have. As a person in charge of hiring, what kind of demos would you like to see in a candidate? What kind of portfolio should a person without demos try to develop for the purpose of trying to get a job?