Until project is not ended (30 days from the start), all funding made are just a "pledge", no credit card is being touched. In fact the real problem could be just for the developer, when on the expire date some user pledged but "forgot" it (yes you can do it). After this, there's a virtual contract and if the starter of the project doesn't respect that, Kickstarter says he need to refund everything, but this is obv outside the management of the site so everything can happen. This is the risk to fund, in real life like on the net, so no real surprise here