11:41:55 AM Dec 19th 2017
Currently, the introduction talks only about the use of violence and gore as a cue that a movie ain't for kids, but there are plenty of examples including early sex scenes/frontal nudity. Movies such as Innocent Blood have their Ms. Fanservice stark naked in the first three minutes of the film (in this case, to convey that this is an erotic horror film, not something like its PG-13 contemporaries Buffy the Vampire Slayer and Arachnophobia).
11:15:21 PM Jul 4th 2013
From reading this page it seems like a lot of examples are being listed that don't fit the trope. Quoting from the introduction: "The R-Rated Opening is primarily for dealing with potential Public Medium Ignorance about genres that are not all filled with family-friendly material, or involve mature "twists" on iconic family-friendly genres/themes such as a Super Hero film from The Dark Age of Comic Books, that's based on a Darker and Edgier Deconstruction of your typical cape. Having someone get shot, die, or even just bleed on screen will very clearly let audiences know to expect things to get much, much more serious and give fair warning for any parent who didn't pay attention to the R-rating but saw "cartoony people" in the movie trailer and thought they were taking their kids into some light-hearted fare." So the R-Rated Opening is a trope used to change expectations when one is going into a work and possibly expecting that work to be family friendly. It doesn't seem to apply for works in which there is no possibility of expecting family-friendly entertainment, yet several examples are just that—a "Friday the 13th" slasher movie, sequels to the "Alien" films, "The Dark Knight" (surely the first Nolan Batman would be enough for anyone to know that TDK isn't a family film). An R-Rated Opening for an R-Rated movie that everyone knows going in will be R-Rated isn't a trope, it's People Sit on Chairs. So I am deleting examples in which there's no reasonable possibility of an "R-Rated Opening" being used to dispel expectations of family entertainment. People going into a Freddy Krueger movie (another example on the page) know what they're in for.