etna87: I agree, 45k of the 50k backers will probably withdraw their pledges close to the end of the campaign. It's a phenomenon that occurs for almost every Kickstarter campaign.
Roman5: Really? I haven't kept an eye on Kickstarter, where has this happened?
As Whitecroc mentioned: It was meant as a joke. I tried to make the numbers very unrealistic, maybe I should have exaggerated further.
(However, if you interpret "almost every campaign" in a certain mathematical sense, i.e. "every campaign except for finitely many campaigns", the statement would be true)