Common sense says that the answer must be a resounding no; that this allegation in an affidavit is both superfluous and irrelevant. Who needs to be authorised to tell the truth? A deponent to an affidavit is simply testifying to her personal knowledge.
In Ganes and Another v Telecom Namibia Ltd 2004 (3) SA 615 (SCA) Justice Streicher said: "The deponent to an affidavit in motion proceedings need not be authorised by the party concerned to depose to the affidavit. It is the institution of the proceedings and the prosecution thereof which must be authorised."
Justice Mabindla-Boqwana giving the unanimous judgement of the Supreme Court of Appeal in Masako v Masako and Another (724/2020)  ZASCA 168 (3 December 2021) was faced with the same issue. Relying on the Ganes decision she found that "[i]t stands to reason that a deponent to an affidavit is a witness who states under oath facts that lie within her personal knowledge. She swears or affirms to the truthfulness of such statements. She is no different from a witness who testifies orally, on oath or affirmation, regarding events within her knowledge. Thus, when Ms Moduka deposed to the founding affidavit, she needed no authorisation from her client.”
Common sense and the law aligned.