You stated Biden's appearance on 2 June was a "surprise appearance." I am not certain what you consider a surprise, but it was known well in advance that Biden would speak at the event. Here is a link to an APP piece that mentions it on 11 May.
http://blogs.app.com/capitolquickies/2009/05/11/biden-with-corzine-for-june-campaign-kickoff/
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