Good, de beers is highly amoral business and there is no way around it. Blood diamonds and lies around them, artificially elevating diamond prices, making up the classic PR campaign that somehow inserted equation wedding=big diamond into minds of mostly US population for few generations.
When I see somebody with diamonds and check with them that they are naturals, its pretty clear what kind of person I am dealing with. To be kind and polite here, its not a nice evaluation and it ends up very precise. I let them know what's the general consensus on morality regarding those stones, its sometimes funny to watch their reactions and at least now they know something and can't anymore argue they didn't. What they do with that info is up to them.