As the editor of my HS yearbook (many years ago), I can attest that students try repeatedly to get something “funny” in the pages. Gotta inspect every bit of copy, every photo, every layout carefully, and with multiple layers of review. The lead photographer was a hilarious, irreverent guy, also some of the other editors. Had to set boundaries and reel them in on occasion. We still had some controversial stuff in the pages that I & the yearbook advisor approved — early 70s. Can’t necessarily go after the publisher or shipper. They produced and deliver yearbooks for so many schools; they won’t catch everything.
When I was in high school it was funny just to get in as many different class pictures as possible (that we didn’t belong in) - fully dressed.
OH yeah. My friend was on the yearbook committee, an artist, and some very innocuous drawing was rejected for being obscene. It was really dumb. So the artists got together and just FILLED that book with hidden sex images. It’s actually really funny. They were little cute things like a bunch of bats hanging upside down and if you look closely one male bat is exposing himself flasher style, an elaborate drawing of a tree, where one large hole in it shows the 2 pairs of feet symbolic of a male lying upon a female therein. Cute little stuff.