That's why you don't "announce" leaks. You either release or don't release documents.
This is one of the reasons why Daniel Domscheit-Berg (and several others) left Wikileaks. He thought it was wrong of Julian Assange to make threats about releasing specific leaks.
Also: Since last year, Wikileaks doesn't have a working submission system. There's still no way to send wikileaks anything right now. Assange stated in several interviews that Wikileaks wasn't accepting documents anymore because they were overwhelmed with the Iraq war/Afghanistan/State cable leaks and that they didn't have the staff to process new submissions. That was only half of the story. The other half is that one of the Wikileaks members that left last year at the same time as Daniel Domscheit-Berg was the guy who coded the submission system. When the coder left, Wikileaks wasn't able to keep the submission system running because there was no one else capable of maintaining it and making sure it stayed secure (given that the submission system is probably the most sensitive part of the site).
Check out
this interview with Domscheit-Berg for more about why he left Wikileaks.