Glad to see someone else has heartburn over them.
My experience with them is at the State appellate level. Over the last few decades, the State courts adopted a custom of issuing unpublished opinions, i.e., opinions that the West Reporters (the standard books you go to to find decisions) are instructed not to publish and which, even if you find one, you cannot cite as precedent. In part this was understandable. Lots of appellate decisions (esp. on the criminal side) rule on nothing interesting or noteworthy, or point out that this case is obviously governed by earlier opinions. No sense wasting paper reporting them.
But I've also seen some where the ruling clearly WOULD have added to or changed the law in a significant way, and which I'm convinced were unpublished simply because the court wanted to go in a way contrary to the law. So it did it, and didn't have to worry about this decision binding the court in a later case where it did want to follow the law.
UPDATE: These are State appellate judges. I think they are on the ballot with approve or disapprove (in the 30 year history of the system, I think there's been just one who lost that vote). That may have affected one unpub that I got. The appeal concerned the "natural life" sentence, then recently created by the legislature as a "real life sentence" (ordinary life was parole-eligible after 25 years).
The Arizona Constitution has a provision that every bill must concern one subject. Case law says the purpose was to prevent omnibus bills where you round up votes by sticking in things that appeal to other legislators, attaching their pet ideas to get them to agree with a bill that, alone, they might vote against.
The natural life sentence was created in a monster of a bill that was even entitled "Omnibus Bill." It had everything. I remember around a dozen provisions -- one that I remember established some sort of a bureaucracy to regulate collector auto sales. Most of it didn't even concern the criminal code, and natural life was just a couple of sentences buried in it. Presumably somebody wanted it and just stuck it on.
I forget what the court of appeals said, but they managed to claim the bill had a single subject and wasn't an omnibus bill. Bottom line -- they were NOT going to be blamed for striking down natural life sentences (and also every other provision of that bill, thus riling the entire legislature). I think they made it unpublished because the reasoning they had to use was tenuous to the point of humor, and they didn't want to be bound in future cases by a ruling that essentially made the single purpose provision meaningless.