A lot of the OG's and chippers that have been in the community a long time and go to meetups regularly, yes, they know each other and there's a high level of trust, I'm sure.
But someone like me, coming into this hobby two years ago, not having been to a meet up, and not meeting anyone here except for a few of the local guys that post here too, my word is all I have, yes. If I sell something and someone questions my sale or whether I can be trusted, I can give a long line of references and refer them to my feedback page to give assurance that I'm not going to rip them off. That, and I took the time to research and read about how things work here before I sold something so I didn't look ignorant, and treated everyone with respect to show that I can be trusted.
Act like an ass or defensive, especially early on, and your reputation and trustworthiness is really hard to get back once it's lost.