The restaurant Kite-Man takes Ivy to is named Martha's Bruce, a vicious wink at Wayne's family, as well as being a reference to the real Ruth's Chris Steak House chain.
The episode title is a pun, referring both to the Praxis bloodline and the line Harley will not cross.
The Praxis family and hero share their name with the Klingon Moon that exploded in Star Trek 6: The Undiscovered Country.