The case was a fairly routine-looking DUI, but the Court of Appeal decided to use it as a vehicle to settle a more general question of law:
Because the first step in this analysis requires us to review the trial court’s findings of historical facts and, in this case, those findings are based in part on a video recording of the event, this court, sua sponte, issued an order converting this appeal from a one-judge appeal to a three-judge appeal and requested the attorney general to file a supplemental brief on the appropriate standard of review. With the near ubiquitousness of squad car video cameras, surveillance cameras and traffic cameras, appellate courts will be deciding more and more cases where some of the evidence is preserved on recordings.
(footnotes omitted). Death of Privacy? got cited for the ubiquitousness point, which is fair enough, although not exactly central to the main issue the court was concerned about.
The standard of review for decisions based on recorded evidence is debatable because a reviewing court ought to be as able to review recordings as is the trial court; the same cannot be (or at least, is not) said about testimonial evidence, since the trial court sees the live witness while the reviewing court sees only the ‘cold’ written record. Traditionally Anglo-American legal systems tend to give a great deal of weight to the seeing of live witnesses by triers of fact, whether or not this in fact enhances accuracy; civil law systems, I gather, do not have the same fetish.
States differ on the appropriate standard of review in such cases, but the Wisconsin Court decided that “clearly erroneous” was indeed the test it would apply when a trial court makes an evidential determination based on a combination of testimony and recorded evidence rather then the far less deferential “de novo” standard urged by the appellant. The perhaps more interesting issue of what standard of review would apply if all the evidence were recorded is not decided in this case, at least not explicitly.