I just received one of these in the mail today, despite my 2011 Roadster being my only Tesla.
I'm wondering whether Tesla actually receives the results at all, or if this is just a marketing survey for someone else. The text does say that the research "is being conducted on behalf of the automobile industry."
I've long had the impression that Tesla allows third parties to send mail to their registered owners. Tesla probably doesn't share the mailing list itself, but perhaps merely facilitates the mail merge. But I'm just guessing based on the sorts of mail I've received over the years.