What is the legal test for holding a written or oral hearing on a citation?

As noted in Law Society of BC v. Johnson, 2019 LSBC 4 (CanLII), 2019 LSBC 04 at para. 24, in determining whether a hearing panel should exercise its discretion to proceed with a hearing in writing rather than by oral hearing, the following factors may be relevant: a. The evidentiary record: A hearing based on written materials will generally require substantial agreement on the facts underlying the citation. If there is a conflict in the evidence or if the parties do not agree on the key facts, then an oral hearing may be required to hear viva voce testimony, weigh the competing evidence and make findings of fact. There may be some cases where it is possible to conduct a hearing in writing notwithstanding that there is conflicting evidence, but in practice we consider that such cases will usually require an oral hearing. b. Whether the parties have provided comprehensive submissions and a complete evidentiary record: If the hearing is to be conducted on written record, it is important that the hearing panel be provided with comprehensive materials with respect to all the relevant issues in the proceedings. If the hearing panel has questions that cannot be resolved on the basis of the written materials, it may be necessary to proceed with an oral hearing. c. Whether the public interest requires an oral hearing: Some cases may raise public interest concerns that weigh in favour of holding an oral hearing. For example, some cases may involve significant media interest. In some cases there may be complainants or other parties who wish to attend a public hearing. Third party interests are not determinative, but they may be considered by the hearing panel when deciding whether an oral hearing is required. It is not necessary to exhaustively define the circumstances in which the public interest requires a public hearing, but there are some cases where an oral hearing open to the public is necessary.