Pseudolaw adherents have been successful in the courts. Not because of their arguments, but because of impatience or frustration on behalf of police and magistrates. That’s generally the only way pseudolaw adherents can have a win, they make law enforcement and judicial officers lose their cool and forget their own obligations.
First example, due to the fact they flustered the police officer and made them forget certain statements they’re obliged to say, like in the Queensland case of Ivan Bortic, where Magistrate Wilkins found that although Ivan Bortic had not complied with directions given to him by Sen Const Sperling, the officer had not correctly warned him that if he did not produce his drivers licence he could be arrested, as was required by the Police Powers and Responsibilities Act.
“In the words used by the officer he did not say “it is an offence to fail to comply without reasonable excuse and that you may be arrested”. He certainly informed him he would be arrested for failing to comply; but he did not mention it was an offence. And for the benefit of the defended, or his fortune, the officer by the omission of those few words has not put himself in a position to be able to prosecute this offence. The recalcitrant attitude of the defendant probably did not assist the officer in choosing his words in the correct form and is fortunate that the officer has not used correct terminology when giving the direction.”
Costs were also later awarded in Bortic v Queensland Police Service  QDC 22.
The Local Courts
The second example, is that they flustered a magistrate unfamiliar with pseudolaw concepts, who then denied the defendant the right to a fair trial, which was later overturned on appeal, like in Harkness v Roberts; Kyriazis v County Court of Victoria (No 2)  VSC 646, most recently cited in Kelly v Fiander.
Kelly v Fiander  WASC 187 was most interesting, Kelly appeared in a traffic court trial proceeding where she engaged in strawman theory antics, claiming “I am Dawn Michelle – Minister Dawn Michelle, executor for the Dawn Michelle Kelly estate.” The magistrate would have nothing to do with this, and basically told her to either acknowledge she was Kelly, or else the matter would proceed on the basis Kelly wasn’t there. She refused, so the trial proceeded summarily and she was convicted.
On the appeal, Vandongen J held that it was not a pre‑condition to reaching the conclusion that an accused had “appeared” that the accused clearly identify themselves in answer to questions from the court, and that an accused “appears” when they are personally before the court (or if they are not personally before the court and instead represented by counsel), and this is so even if the accused refuses to identify themselves. Vandongen J overturned the conviction, deciding the magistrate did not afford her a fair trial, proceeding as if she wasn’t present even though she was. The decision established a procedural rule, that a pseudolaw adherent is actually present, despite not identifying themselves by what they perceive to be their “strawman duality” name.
It was first adopted by Tottle J in Kwok v Gordon  WASC 325. Noting that those who “disrupt and delay the administration of justice in the State’s busiest court .. are the cause of considerable frustration to magistrates”, Tottle J said:
“…it was apparent that the appellant was in fact the accused even though she had refused to identify herself as such. Thus, by proceeding to hear the charge under s 55 of Criminal Procedure Act the magistrate erred in a manner that gave rise to a miscarriage of justice.”
The following day in the same Court, Forrester J set aside more convictions, sentences and costs orders in Reynolds v Nonkovic  WASC 326 referring to the rule observed in Kelly v Fiander  WASC 187. The frustrated primary magistrate said in the past he “had some lengthy dealings with Mr Reynolds as a result of being the only magistrate…” who “indulges in these nonsensical arguments that have been resoundingly disabused by the Supreme Court”. Forrester J held that:
“…the appellant was the person the subject of the prosecution notice. It was his refusal to acknowledge his name as being that contained in the prosecution notice which resulted in her Honour refusing to ‘recognise’ him as an accused in the matter. While it would no doubt have been time consuming, and frustrating in the context of a busy and high-volume court, if her Honour was not satisfied that the appellant was the person named in the prosecution notice, it was necessary for her Honour to have made further queries before determining whether the appellant had not ‘appeared.’ From previous experience, the learned magistrate was aware that there was another means available to her to verify the appellant’s identity. However, rather than utilise it, her Honour had the appellant removed and dealt with him in his absence.”
Indeed, the judicial frustration was apparent in Dent v Commissioner of Police  QDC 235, where the appeal judge agreed that the magistrate had erred by not giving reasons. after blurting out that Justices of the Supreme Court were “sick & tired of this rubbish”.
Similarly Wilson v Garlett  WASC 506, after a magistrate determined an obstruction charge in the defendants absence. And Hainaut v Queensland Police Service  QDC 223, where strawman duality capers again flustered the magistrate. On appeal, the conviction, sentence and orders were set aside without remittal.
A third reason, I would put down to underestimation. Often pseudolaw beliefs are based in at least half truths, and with all the media attention and the use of the “cooker” pejorative, they are underestimated, which is never a good move. For example, recently NSW Police ignored one of those “trespass signs” demanding penalties in gold and silver that people online have generally been laughing about and disregarding as stupid. The occupants sued NSW Police in Romani v State of New South Wales  NSWSC 49, and were awarded $18,300 in damages.