Counterpoint:
Occasionally authors of linked pieces or subjects of stories drop by to participate in the discussion; e.g., pixel artist Blake Reynolds, game developer Brianna Wu.
I realize that they are the rare positive exceptions of new posters, but I’d hate to think that some added friction or waiting period would get in the way of interesting people stopping in and talking about their work.
I know that other forums like the model where new commentors to have their first post moderated prior to getting unrestricted posting ability, but I don’t know how that scales with the BBS volume and staffing.