Ripple is based on trust. it will fail.
All transactions are based on trust. Since mankind first began bartering.
They're based on Trust because Fear is the backstop. All beasts are resource dependent and vulnerable - none of us are Gods. I'm agnostic about Ripple, but either I'm an imbecile or I just can't put together in my head how it actually works.
It works on the theory that when that guy borrowed that tool, you actually get it back.