"Filing a false report" is a slang term among the Republic City wlw community for trying to get a girl's attention because so many wlw have wandered into the station like "uuuhhhh someone stole my handbag and I think the Chief should personally handle this case".
Kya has been sitting on this information for 10 years waiting for the Right Moment to drop it on Tenzin.
Something I love about Banana Fish is how stupid the name sounds, even now I read it and the image of a half-banana half-fish hybrid comes into my mind sometimes. And it's so funny because Banana Fish is so dark and honestly raw you wouldn't expect a name like that but then you watch it and the names makes perfect sense