Do you use any exchange currently? How can you be sure they will credit your account with the amounts you send in, and when you request for it, that they will send your funds back?
This is not specific to ripple, though. We extend banks our trust, probably under the assumption the government will have our backs if the banks misbehave, thus shifting part of our trust to them. In the end it's all down to who we trust, how how much we trust them for (just ask some of the people in Cyprus about that).
As a ripple gateway operator I want to say you can trust me, and so on, but in the end I am only as trusted as your perception of it, and that's an individual decision. Usually we're forced into these trust relationships (wanna get your wagers? Open a bank account.) but with ripple you can actually decide that for yourself.
yes well gateways at least, have some financial intensive to have a rep as they want to make money out of the next trade....individuals, not so much.
True. It was never, to the best of my knowledge, a part of the design that people would trust each other for currency. That's a concept that for the most part works poorly 'in real life' too. But the system does allow for it and there are use cases where it might make sense (see the DYM case from TTBit or the FAV heated discussion).
All in all I think you shouldn't (ripple) trust anyone or anything that your don't (really) trust, it's that simple.