Google has made a small change to the Google My Business Guidelines explaining and clarifying the roles of practitioners. Joy Hawkins posted in the Local Search Forums that the line that was added was "Sales associates or lead generation agents for corporations aren't individual practitioners and aren't eligible for a listing."
You can see those specific guidelines over here:
Joy explained "I know a while ago I asked Google if Colan would be allowed a practitioner listing. He's public facing and technically has his own client base. They told me no, marketing companies wouldn't qualify for practitioner listings. I think this new update helps clarify that a bit better."
Some local SEOs want to test it out to see if Google takes action if done otherwise.
Forum discussion at Local Search Forums.