You are correct. Trust from end to end is necessary.
Actually, Steemit as a social media platform gives us quite a bit of insight into the character and behavior of others on the platform. This makes it easier to form a "network of trust" that makes transactions like this possible and successful.
True, it really depends on how the trust works. Understanding the overall behavior and others character on Steem can actually be a reference to an individual credential. Agree on that :)