Trivia: When Payback attacks Warren's store, look at the till - apparently, they still use paper money as well as creds.
Bruce: By the way, exactly what did you say in that group to get Payback so mad at me? You must have given quite a convincing performance.
Terry: Who said anything about performing?
Bruce: Who are you?
Payback: I'm your worst nightmare!
Bruce: You have no idea what my nightmares are like.
Payback is similar to a character in the Batman comics called Anarky, in that both are young boys acting as anti-heroes, using special suits to appear taller then they really are.
The function at which Payback attacks Wayne is at the Vreeland Marquee Hotel - Veronica Vreeland was a recurring character on TAS, and her daughter Bunny was the debutante rescued by Bruce in his last adventure as Batman (in "Rebirth (1)").