When do depositions require a court reporter? I've looked at some rules of civil procedure that suggest that a deposition must always be attended by a court reporter. But my impression (perhaps resulting from too much TV) was that depositions these days are normally just videotaped, and the tape shared with both parties. Is that just fiction? Or is it allowed – or even customary?
Depositions must always be attended by a court reporter in every jurisdiction I have ever encountered (including Colorado, New York, California, Wyoming and Florida). Alaska may be an exception. Its state constitution creates a right to participate in many kinds of legal and legislative proceedings remotely because the distances involved are often so great. The court reporter administers an oath to the witness, keeps track of exhibits, impartially records what happens (usually stenographically and with an audiotape) and then reduces it to a transcript later, a process assisted by having been there when the testimony was given (and allowing for the court reporter, for example, to request spellings of words during breaks). A videotape can be used in addition to the court reporter and sometimes this is done when it would be helpful for understanding a highly visual topic (e.g. in a patent case where someone is explaining a 3D object) or when a witness is expected to behave badly or is known for problematic voice character or body language. Court proceedings in a courtroom are often audiotaped with a judge present but without a live court reporter present. Appellate court arguments are frequently live streamed over the Internet. There may be some jurisdictions where it is possible to have an oath administered by a notary and simply audiotape or videotape the deposition, but that would be very rare in every jurisdiction of which I am aware.
I don't think there would be such a case. The Supreme Court itself does not allow cameras in its courtroom. Also, when Florida wanted to bring cameras into Florida courtrooms, the Supreme Court said in the 1981 case Chandler v. Florida: Absent a showing of prejudice of constitutional dimensions to these defendants, there is no reason for this Court either to endorse or to invalidate Florida's experiment. It's also worth noting that "the jury may not be filmed" and "The Florida Supreme Court has the right to revise these rules as experience dictates, or indeed to bar all broadcast coverage or photography in courtrooms" were two of the specific rules that the Supreme Court noted Florida had implemented. Although those particular rules were not at issue in this case, the Court made no further mention of them, and thus perhaps tacitly approved of their constitutionality. Given that there does not seem to be a general right to film in a courtroom, it seems unlikely that there would be a right to film jurors in particular. Furthermore, this page lists the courtroom camera rules for several states. In many of them, filming jurors is prohibited. Presumably, if there was a ruling that this was unconstitutional, they wouldn't have those rules.
There are two cases to distinguish: information that the other party does not want to give without court order, and information that the other party may not give without court order. Only the former case matters, of course, since the latter by definition requires a court order. So, if the other party is legally capable of giving the information, but it's commercially not sensible for them, then you'll need to sweeten the deal. And that's business, not a legal question anymore. In other words: there's no legal instrument that's at the same time equal to a court order but also different from one. When you need a court order, there's no alternative to a court order.
A subpoena is nothing more than court process compelling someone to testify as a witness or to produce documents in their possession, custody and control, or both, usually in connection with a court case. Most people who are subject to a subpoena are not being asked to offer testimony that could implicate them in a crime. They simply have evidence relevant to a case. For example, bank records are routinely subpoenaed to generate evidence that can be used in a civil or criminal case against someone, even though no one accuses the bank of doing anything improper. Many witnesses are also just not bothered to testify or actively don't want to testify, even though the evidence would not personally reflect poorly on them in any way, if they are not compelled to do so. For example, they may simply be very busy at profitable activities, or may fear retaliation from people involved in the case. Also, subpoenas are not infrequently issued where the witness is personally happy to testify but needs court process to get permission to be away from work or other obligations. A subpoena can also overcome legal obligations to not voluntarily provide information even when it is not legally privileged. For example, a lawyers ethical obligation not to voluntarily share information about a client (even information that isn't attorney-client privileged like the existence of an attorney-client relationship or the amount of money that the attorney holds in a trust account for the client's benefit) is broader than the attorney-client privilege and a lawyer can be compelled to provide such information by subpoena. To invoke the 5th Amendment in a case where you are not a defendant, you must have some good faith belief that your testimony would expose you to criminal liability, something that the vast majority of witnesses under a subpoena do not. You cannot invoke the 5th Amendment, for example, to protect yourself from having to testify regarding something that may be highly embarrassing and may even constitute a violation of the law, but is not a crime. For example, you can't invoke the 5th Amendment to prevent yourself from having to admit under oath in court testimony that you cheated on your boyfriend with someone else, or that you forgot to lock up the office the night before it was burglarized, or that you lied about having won a military decoration that you publicly claimed to have won but really didn't, or that you are in default on your mortgage, or that you are out of legal immigration status. The 5th Amendment can also not be invoked to prevent you have having to testify about violations of professional ethics that are not crimes. For example, an attorney could be compelled to testify that she failed to keep confidential information private by telling her bartender client secrets. A subpoena is basically useless against a defendant in a criminal case, who has the right not to be compelled to testify in his or her own case. But, in a civil case, you can subpoena someone to testify against themselves and they then have the choice of invoking the 5th Amendment and having an adverse inference entered against them (usually resulting in them losing the case if they are a party to it), or not invoking the 5th Amendment and testifying even though truthful testimony on the subject may be incriminating and may be used against you in a criminal prosecution. Someone can also be compelled to testify regarding matters that could be self-incriminating in a civil or criminal case if someone with authority to do so (generally the relevant prosecuting attorney) grants the person compelled to testimony immunity from prosecution (usually all that must be granted is immunity from prosecution based upon the testimony offered, called "use immunity", which is still less than someone admitting to criminal conduct might need to feel comfortable if testifying voluntarily).
Your assumptions are incorrect. Courts allow oral arguments (when they do allow them) so that attorneys have a chance to better address a judge's concerns. The idea is that it lets an attorney not only present the core of his case, but it also lets him address any problems with his reasoning that the judge may have or help the judge explore a complicated question. Without that all you have is the back-and-forth in writing with opposing counsel, which is useful, but may not actually address the issues that are important to the judge. There is some difference in how you present arguments on paper as opposed to in oral argument, but the distinction is largely one of style rather than substance. An argument that is great on paper is still great when presented out loud, you just present it differently because you are presenting it in a different medium. For example, you have to present oral argument with the assumption that the judge may interrupt you at any time to ask a question they are interested in, derailing your entire pre-planned argument into a tangential point the judge considers important. This is great because it lets you address what the judge is concerned about, but it requires a different preparation and some changes to the format of your argument. For example, while you will front-load both oral and written arguments with a roadmap, both your roadmap and your first sentence are much more important in oral argument.
What are the factors in weighting whether to disclose substantive evidence vs. using it for impeachment at trial? In an adversarial system (such as that in the jurisdictions in the U.S.) the surprise factor is disallowed on trial. I am not knowledgeable on the procedural exceptions, but generally speaking the documentary evidence (including deposition transcripts) has to be filed during the discovery stage of proceedings. A discovery deadline is set up during case scheduling, and extensions of that deadline have to be requested via motion. There is the slightly related concept of sequestration of witnesses whereby inconsistencies may serve to impeach a witness's testimony, but that is different than withholding from the jury any pre-existing evidence that a plaintiff would like to be considered on trial (whether for impeachment or otherwise). Also, it is in the injured party's best interest that the jury get to see the evidence rather than have it merely rely on a witness's reaction of surprise. The wrongdoer's lawyer will try to confuse the jury and thus outweigh the jury's perception of a "surprised witness", but that attempt is likelier to fail if the jury has the evidence with which to compare the witness's testimony at trial.
The issue is more one of what an attorney is ethically authorized to disclose pursuant to professional ethics rules (Rule of Professional Conduct 1.6 as enacted locally) more than one of attorney-client privilege. Attorney-client privilege governs what someone can or cannot be compelled to disclose without their consent (usually by subpoena). Attorney confidentiality, in contrast, governs what an attorney can disclosed when not compelled to do so by something like a subpoena. Generally, disclosure of confidential client information is allowed if it is in furtherance of the representation or authorized by the client (there are also other exceptions but those aren't really any different in a two lawyer v. one lawyer situation). Often when two attorneys represent the same person (and the disclosure won't waive the privileged nature of the information vis-a-vis third-parties under a joint defense theory), disclosures from one attorney for a person to another attorney for a person will do that. In practice, however, the analysis could be quite fact specific and there isn't really a bright line rule governing when it would or would not be allowed.
As I understand it, legal procedure in Common Law jurisdictions (e.g. the UK) is primarily based on evidence given by a person. Paperwork exists to verify that someone has not misremembered something, but even when you have paperwork you need to have someone testify that this is the right paperwork and it hasn't been forged. A piece of paper on its own means nothing. In practice of course the two sides will agree to accept routine matters rather than dragging lots of third parties (e.g. the post office employees) into court to no point. In the case of a letter where you need to prove it was received, the sender will testify that they sent the letter and that the copy they have introduced into evidence is a true copy. The proof of delivery merely shows that the item wasn't lost in the post. If one party testifies that they sent a letter and the other testifies that they merely received an empty envelope then someone is lying, which is a crime meriting further investigation.