It's funny when people ask about "rules" as thought this industry is any way regulated. Do you think there's some kind of femdom council that will take rulebreakers to task?

In practice, similar names aren't actually that much of an issue. I don't know if you've noticed, but ads generally contain photos! Two Mistresses with the same first name who look wildly different aren't going to have much trouble, especially if they use different titles/last names, are based in different cities, and/or have different specialties. At worst, they come off a bit cliché for choosing such a popular name.

We don't want to be confused with each other, either, and we do strive to distinguish ourselves in various ways. Usually it works.

I probably would not be Maya if anyone had warned me that there was a very big deal Mistress Maya in Chicago when I started. That said, it's never caused any confusion.