This is first-year law school stuff.  But the 4th Appellate District devoted a lengthy footnote to this basis proposition in Fierro v. Landry’s Restaurant Inc


In summarizing the factual and procedural background, both parties failed to support numerous factual assertions with citations, or at times accurate citations, to the record on appeal as required by California Rules of Court, rule 8.204(a)(1)(C). Our independent review of the record on appeal has not helped in finding support for some basic and many extraneous facts contained in the parties’ briefs. Absent a party’s accurate record reference or our independent verification, we have not considered the party’s factual recitation. (Rybolt v. Riley (2018) 20 Cal.App.5th 864, 868 [appellate courts may ” ‘disregard any factual contention not supported by a proper citation to the record’ “]; County of Riverside v. Workers’ Compensation Appeals Board (2017) 10 Cal.App.5th 119, 124 [appellate courts ” ‘ignore’ ” factual statements without record references].) An alternative basis that supports the same result is the rule that we are unable to accept counsel’s argument on appeal as facts. (See In re Zeth S. (2003) 31 Cal.4th 396, 414, fn. 11 [“the unsworn statements of counsel are not evidence”]; Davenport v. Blue Cross of California (1997) 52 Cal.App.4th 435, 454 [“unsworn averments in a memorandum of law prepared by counsel do not constitute evidence”].)

More important than the slap on the wrist footnote is today’s decision by the California Supreme Court to grant review and transfer back to the Court of Appeal with directions to vacate its decision and to reconsider in light of China Agritech, Inc. v. Resh

This means the Court will have to reconsider its order reversing a trial court’s sustaining defendant’s demurrer without leave to amend on statute of limitations grounds.

The underlying issue is a fairly complicated and esoteric procedural issue.  The footnote quoted above addresses a more quotidian problem and provides some useful citations.