
According to a pair of reports sent to Gamasutra, the ESRB is paying closer attention to game trailers, requesting they be pulled if they contain inappropriate content. Apparently, the organization contacted D3 Publisher and told them:
The ESRB requested that D3 pull the trailers, but noted that someone's "ability to capture direct feed footage for distribution on your site" wasn't covered by the notice.
Apparently, 2K Games got a similar love note regarding trailers for The Darkness, saying "the ESRB requires that all trailers for Mature ("M") and Adults Only ("AO") rated games be appropriately age-gated." The statement went on to say that "Game publishers that do not comply with the age gate requirement are subject to enforcement actions by the ESRB," though it didn't go into detail about just what those actions might be.
ESRB Enforcing Game Trailer Ratings [Gamasutra]