Kerry, I disagree (I know this is a first, lol). But
I think a name like Prohibition Room will be iconic and that its 'misleading' name would STICK in people's mind.
Imagine someone from out-of-town comes in and asks where's a good place for continental cuisine in the city. He is told to go to the Prohibition Room, and you can see the response. .....
To me, speakeasy is just for drinking and things you can't do in mainstream. Prohibition Room leaves the mind looking to discover 'exactly what this place is.'
And if the food is good and decor is great - it should become an OKC institution worthy of its location.