Well, it would be pronounced the exact same way to say "are you [formal] new?", but in the written form, the word "sie" needs to be capitalized in order for it to mean "you [formal]".
If the sentence were "Sind Sie neu", then "Are you [formal] new?" would be completely correct. In this case, since it's lowercase (and because of the conjugation "sind"), it translates to "they" instead.
Hope this helps!
Ok, I'm far from an expert, but does it sound to anyone else like the voice is saying "Sind Sie neu" as in "Are you (formal) new?"
I know there's hardly any difference between the two, but it sounds to me like a person meeting someone new, rather than asking if the plates on the table have been newly purchased...