A few people have mentioned this, and I actually considered using it as a joke option when I made the poll. The reason I didn’t is that the question is one of fluency, not mastery.
And, on a sidenote, a linguist is a person studying language structures and history, not a person who speaks many languages:P
Yes, but when you go and learn a language you effectively become a linguist, at least in regards to the language you’re studying. This is because nearly every language course, whether it’s in a classroom or a “Teach Yourself”-type course-in-a-box, includes sections on the history of the language.
The results of this poll have actually surprised me a bit; for some reason I was expecting an overwhelming majority to be multilingual. Well, I’m allowed to be wrong now and then.