I'm curious, why would it be bad if the organizers of a conference made that mistake, but it's not bad if the attendees do?
And yes, he means that people walk up to Randall and say "oh hey, Brian!" and vice versa. Really, really often. Sometimes repeatedly. They're different heights, they don't even look like each other at all. They're just usually the only two black guys there. It happens at more than just Ruby conferences...