Analysis of information sources in references of the Wikipedia article "Motion Picture Association film rating system" in English language version.
The rating restricts anyone under the age of 18 from attending a film.
In most cases, that means enforcement as though the movies were rated NC-17 — where no one under the age of 18 can be admitted even with accompanying parents or guardians."
Formally instituted in 1990, the restrictive rating aimed to signal moviegoers that a film included adult-oriented — but not necessarily pornographic — content and made those movies off-limits to anyone under 18.
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