The problem with By Referral Only is that, well, it's not. Or, rather, you're not.
To get away from the commas: how are you going to prospect strangers or at open houses and then give them a card that says, "By Referral Only?" 2B1 Call 1?
The program and coaching, I am told by associates, is excellent. But ... I'm just not By Referral Only. You don't need to know someone to use me. And that's the credibility gap created. "Everything I say is true, except ..."