U.S. Patent No. 8,917,772 relates to encoding and decoding video and is essential to a standard (page 2). A working draft is the prior art and was allegedly available during a July 2011 meeting, on a website through four step navigation with the last step being selection of one document from a list of hundreds organized by number on October 2011, and by email to members of the working group and possibly others (pages 3-4). Since the draft was not created until after the meeting, the meeting is not public disclosure (pages 10-12). By starting navigation in the website based on city of meeting and no evidence of ability to search, the document is not publicly available (pages 12-13). The draft is not publicly available if only the creators can access (page 14). The email could have been to other people than the creators (pages 17-18). It is the availability of access that matters, not actual access (page 18). The case was remanded to consider access to the email (page 20).
Hindsight: Having a large number of creators does not result in public access. At some point, I would guess the number is sufficiently large to result in public access. Consideration of whether a person of skill in the art would receive the email and expectations of confidentiality may result in an email being a public disclosure or not. Given the various circumstances that may or may not result in public access, an application may be pursued despite some access.