“Disclosure of parties pre-suit: Is there a legal principle which obligates one party to provide relevant documentation, evidence, etc… requested by the other party before suit is filed? I’m not talking about discovery that happens after suit is filed.”
There is one exception in Federal Courts (Federal Rule of Civil Procedure 27), that has been interpreted to allow either party to depose a witness who is likely to die or otherwise become unavailable before the lawsuit is filed. Some states have also passed statutes that allow for pre-suit discovery. For example, Texas, Alabama, New York, Ohio, Pennsylvania, and Vermont all have statutes that allow varying forms of pre-suit discovery. The availability of pre-suit discovery in state courts is usually predicated on their being some denial of justice without it, but may also be available for parties to determine whether they in fact have a lawsuit to bring. If you’d like to read more about pre-suit discovery, there is a good law review article that you can find online, for free, <a href=”http://scholarship.law.wm.edu/cgi/viewcontent.cgi?article=1027&context=facpubs” target=”_blank”>here</a>.