Here the question is not rules. The question is what they did. Either they did this thing or they did that thing. Very simple.
Hey, I'd like to know what their strategy is too. I'd prefer not to have to respond to a lawsuit if a Borrower ever comes knocking. However, they won't talk while the case is active, so this is 16+ pages of worthless sound and fury. Luckily, I enjoy Board-Warrioring in a hurricane environment.

The best way to get Prosper to respond, is to tell Mr Gaerke to subpoena Prosper's Lender records, and then amend the complaint to include all the Lenders. Prosper will need to act fast, and publicly, to save their business model.
NOTE: On that last part, I am serious. It is the only way to get Prosper on record, with specifics, in court, and in public, about how their policies work. Despite what people think, I am not a Prosper Cheerleader. I simply think you guys are prone to hyperbole, panic, and overreaction.