No, this has nothing to do with returning your books late.
Turns out, you just have to masturbate in the one in Racine, Wisconsin! It totally worked for Tyree S. Carter, who, after being caught openly shaking hands with the one-eyed milkman in the Racine public library, was released on a $1,000 bond. One of the conditions of that bond? That he “Stay out of all the libraries on the face of the Earth.” Crafty junior high school students take note: if you don’t want to go to study hall ever again in your life, just get arrested furiously pleasuring yourself in the biography section of your school’s library! (Legal note: Don't ever do this.)
Still, perhaps Mr. Carter is a bigger genius than we give him credit for. Hate the dentist? Just flog your wiener during your next cleaning! And who wants to go to the DMV, ever? Slap your Vienna sausage during your next license renewal and you could be free for life! (Further legal note: Really, really, don't ever do this.)
Regardless of lifetime bans, it seems the library is really the inexplicable masturbatorium of choice for the discerning serial knob tickler. Like this guy, this chump right here, better believe this dude, a guy who fell foul of a hawk-eyed firefighter, and this fine upstanding citizen who was just “near” a library. In short, for some weird reason, people really like masturbating in libraries. Even the ladies.