There's been some new changes to how the ESRB rates games.
The Entertainment Software Rating Board (ESRB) has now ruled, in its industry followed guidelines, that mature-rated demos and trailers can now be presented without age gates restricting the content. There is a catch however - content must still adhere to the stipulations for 'general audiences' and be approved by the ESRB.
Other adjustments to how things are being done include allowing software to have mature-rated content packed in with lower age-rated titles. For instance - a Far Cry 3 trailer packed into a Raving Rabbids title. Barring research (which wouldn't exist for that example) correlating the audiences of each game to one another.