The recently opened Aura Resort which a part of the Wyndham property in Cozumel has quietly informed a few guests that it is a "clothing optional" resort for those who wish to enjoy that "lifestyle" Considering the Aura's placement in one huge resort complex there is a very good chance this will spill out onto the very busy beach in front of it. There is no mention of the policy at their web sites but they have said so in at least 1 email that I know of when questioned on the policy.
http://www.tripadvisor.com/ShowTopic-g1508..._Peninsula.html
and also
http://www.tripadvisor.com/ShowTopic-g1508..._Peninsula.html