Comment 3 for bug 1724685

404 doesn't mean something/anything was not found. It specifically means that the requested resource (from the URI) was not found. In this case, that would be trust, which is obviously nonsensical when you're creating a trust.

400 would be a much more typical response for something like this. As is often the case with REST, there is no HTTP status code that is a perfect fit, but it comes the closest. That said... I'm sure I had a reason for opening this way back when, but I don't remember what issue this was causing anymore, so... low priority.