Parties love to mark things "confidential" in discovery (by "parties," I mean defendants in most cases).  Protective orders that allow for such designations also typically require, generally, that "confidential" material be submitted to the court provisionally under seal.  However, this general framework is frequently abused.  In Overstock.com, Inc., et al. v. The Goldman Sachs Group, Inc., et al. (November 13, 2014), the Court of Appeal (First Appellate District, Division One) examined the propriety of the trial court's sealing orders, reaching other interesting questions:

On our way to reaching these conclusions, we address several issues pertaining to sealing orders that have remained unsettled, including the reach of California Rules of Court, rules 2.550 and 2.551, and media participation in sealing hearings. We also discuss tools available to the trial courts to deal with abusive litigation tactics impacting the handling of sealing issues. Indeed, we are appalled at the burden the parties foisted on the trial court here and view this case as a companion to the decision of our brethren in Nazir v. United Airlines, Inc. (2009) 178 Cal.App.4th 243, 289–290, decrying unnecessary and oppressive summary judgment tactics.

Slip op., at 2.

"Nearly all jurisdictions, including California, have long recognized a common law right of access to public documents, including court records."  Slip op., at 8.  "More recently, many jurisdictions, including California, have recognized a constitutional right of access to certain court documents grounded in the First Amendment."   Slip op., at 9.  "Not all documents submitted or filed by the parties, however, fall within the ambit of the constitutional right of access. NBC Subsidiary hastened to add the courts have held 'the First Amendment does not compel public access to discovery materials that are neither used at trial nor submitted as a basis for adjudication.'"  Slip op., at 10.  "In response to NBC Subsidiary, the Judicial Council promulgated 'the sealed records rules,' rules 2.550, 2.551."  Slip op., at 11.

Turning to an unsettled question regarding the application of Rule 2.550, the Court rejected the construction argued by the defendants, which would have left it up to the trial court to decide first if it was relying on material before deciding whether Rule 2.550 applies:

Defendants maintain Mercury sets forth a bright-line standard: confidential discovery material merely filed (or, more accurately, lodged) with the court, but not actually “considered or relied on” by the court in connection with the basis on which it rules, is not “submitted as a basis for adjudication” and, thus, is not subject to the sealed records rules. We do not agree Mercury can or should be boiled down to such a limited view.

Slip op., at 21.  Instead, the Court held that by "submitting" material for adjudication of (non-discovery) pre-trial motions, the submitting party triggered application of the sealing rules: "defendants’ narrow construction would necessarily mean sealing decisions would be made after-the-fact—that is, after the trial court issues its substantive ruling—because only then would the ground or grounds on which the court rules be known."  Slip op., at 23.

After holding that materials "submitted" for adjudication are properly regulated by the sealing rules, the Court then discussed the consequences of submitting irrelevant material as part of a pre-trial motion.  "As every court to consider the question has observed, the right of access applies only to discovery materials that are relevant to the matters before the trial court." Slip op., at 25.  After raising the subject of irrelevant material, the Court turned to abuses related to the sealing rules:

The problem is two-fold—parties who fail to exercise any discipline as to the confidential documents with which they inundate the courts, and parties who indiscriminately insist every document satisfies the rigorous requirements of the sealed records rules. This case exemplifies both.

Slip op., at 26.  Describing the abuses, the Court said:

Plaintiffs submitted a veritable mountain of confidential materials in opposition to defendants’ motions for summary judgment. Entire documents were submitted, when only a page or two were identified as containing matter relevant to the issues. Multiple documents were submitted to support a claim, when one would have sufficed. No mention at all was made of hundreds of the exhibits. Inundating the trial court with this deluge of confidential materials was brute litigation overkill. (See Nazir v. United Airlines, Inc., supra, 178 Cal.App.4th at pp. 289–290.)

Slip op., at 26-27 (footnotes omitted).  The Court encouraged trial courts to sanction parties for abuses or strike improper material to curb such abuses.

Next, the Court discussed the evidentiary requirements for sealing:

A party seeking to have records sealed under the sealed records rules must make an evidentiary showing sufficient to support the findings required by those rules. (Rule 2.551(b)(1).) While “conclusory or otherwise unpersuasive” declarations that parrot statutory or rule-based requirements are generally inadequate (Providian, 96 Cal.App.4th at p. 301), the privacy interest in some documents, like medical records, is so apparent a declaration is not required (Oiye, supra, 211 Cal.App.4th at p. 1070).

Slip op., at 29.  The balance of the opinion, nearly 30 pages, sets forth the Court's analysis of the propriety of the sealing order for specific documents.  In many instances, the Court held that either a small portion of a long document should have been sealed or the entire document should have been stricken.