OK, I might well have got the wrong end of the stick here, but surely it is grossly impolite to refer to someone in the third person while they are actually present? Always use their name, even if not directly addressing them.

Of course, the possessive pronoun presents some issues, but I go on the evidence of my eyes, applying the pronoun I see, unless requested otherwise.

As to the use of the third person plural to indicate a single individual, I suppose it’s no sillier — and no more impolite — than using the second person plural to address a single individual, which nowadays almost everyone does.