"You could sabotage some Kickstarter projects by pledging a large amount then blacking out a minute before it ends."
https://twitter.com/tlrobinson/status/305017672226205697
Interestingly, Bitcoin has features to make this sort of thing impossible, even without a trusted intermediary holding onto the funds: https://en.bitcoin.it/wiki/Dominant_Assurance_Contracts https://en.bitcoin.it/wiki/Contracts#Example_3:_Assurance_co...