First, I have yet to see "porn" in any hotel. While some of the stuff might come close, it is not porn, at least not based upon the community standards in most of the places I travel. Second, the hotels are not selling those movies to minors. They are selling them to consenting adults who have to go the extra mile to order the movies so as to minimize inadvertant exposure. If a minor is able to watch porn, then its because mommy and/or daddy aren't doing their jobs.
Is it still porn if condoms are used? /s