East 10th Street and Third Avenue last night via the Bagel Guy.
Per the sign, possibly a fake but still entertaining — "no reward."
"I don't even want this bike back. I just made these flyers to tell you that I hate you, bike thief. I hope you ride my bike without a helmet and get hit by a monster truck. I hope my bike takes you straight to Hell."
Ah, so the sign is old... but apparently people are still putting them up... perhaps to help sell these T-shirts. Per the comments, the flyer is the work of David Shrigley.