The original Scrub Clubbers' names, with the exception of Taki and to a lesser extent P.T., are just nicknames.
They might actually be called something completely ordinary, like (for instance) David, Mary, George, Cody, and Seth, but when the club was founded and/or when they got their superpowers, they decided to go by the names Hot Shot, Chill, Scruff, Squeaks, and Tank respectively either because they were given their nicknames, for anonymity, or just because they thought the nicknames sounded cool.P.T.'s real name might be something like Patricia Thomas or Penelope Thompson, but when she became a Scrub Clubber, she thought it was a funny coincidence that her initials were the same as "paper towel" (what she turned into), so she decided to go by her initials instead of adopting a nickname.
That leaves the question of why Taki didn't get a nickname. Still worth thinking about, though.
