It's curious to me that this news report mentions no involvement of library staff

Transcript (plus an RG comment in parenthesis):

[Studio newsreader]  A girl snaps this picture at the Greenfield Library.  You may see just a bunch of books but 12 News Max Seigle shows us what's behind that stack that prompted a sting operation.

[Reporter] If you look closely, you can make out a man peering through a bookshelf.  Police say the 27-year-old was stalking two teenage sisters.  They noticed the individual had been watching them for the last six weeks.)  

(And never notified library staff???)  6 friggin' weeks?)

He was following them around.  Everywhere they would go, they would see him.  One of the teens took pictures of the man.  She showed the photos to her dad.  He called police, who set up a sting.

12 News obtained a search warrant, which said they arrested the man, who they found engaged in a sex act. 

According to the search warrant affidavit here, the man told police he would come here to the library before school let out after three to four times a week.  What makes this all even more shocking is the police department is right next door.

Police say the man never touched the girls, but he told them he's done this at least 20 times, and numerous other times with several other girls at the library.  They also learned he has a juvenile sex assault record.

[Unidentified interview subject wearing a Greenfield Police Department lanyard.]   It's disturbing, to say the least, but.....it's unfortunate that these things are happening in public places like this.  That is why we have to be vigilant. If children are concerned about anything, we urge them to come forward and we'll obviously look into it.

[Back to reporter] Police say if other kids cross this man's path, parents should let them know,.

[Studio newsreader.]  Charges are now pending against the man as he sits inside the Milwaukee County Jail.
 

Final comments.

I didn't find an appropriate library behavior policy or code of conduct on the library's website.

I will definitely be sharing this news report with my spring semester Public Library class.