That would depend on the folks implementing the API
In it's current state, I'd look at the API to check for reserved / premium names (or something that's profane).
If it makes sense contextually: imagine if you were building the next Twitter. I'm guessing you'd want to have a way to charge for premium names and in-turn need a way to detect what's premium. For the most part, first and last names are pretty premium and people pay (they do!) for such usernames.
In it's current state, I'd look at the API to check for reserved / premium names (or something that's profane).
If it makes sense contextually: imagine if you were building the next Twitter. I'm guessing you'd want to have a way to charge for premium names and in-turn need a way to detect what's premium. For the most part, first and last names are pretty premium and people pay (they do!) for such usernames.