Well, using umbrellas as a weapon is, you know,
a real thing. I could definitely see one of these uses for a homocide in a Nolan film.
But when it comes down to it the Penguin is a guy who dresses in a dapper fashion, and is fat and wealthy. He doesn't need to be less realistic then Brother Mouzone of
The Wire. Of the more iconic Batman villains he's one of the easier ones to stick into a 'realistic' story - far more so then the Joker, and mountains more so then the Ra's character.