I say that because it may or may not be noteworthy, but after watching "A Matter of Honor" this evening, I just now realized that the Hayward case was either mentioned or referred to in three separate episodes:
this one, Publish or Perish, and Double Exposure.
Of course if "Troubled Waters" had been referenced again in "Last Salute To The Commodore", Columbo could have stared at Charles Clay for a moment thinking back and then he might have shaken his head and said "Tisn't." :D
Sorry, I had to get that thought out of my system! :)