This was uttered in a general session meeting at a conference.  The speaker was trying to raise an issue that was well-known to all but was avoided in discussion.  I believe it is a mashup of “the elephant in the room” (a serious problem that everyone is aware of but choose not to mention) and “out in the open” (expose something for public knowledge).  The beauty of this malaphor is that it contains idioms that are opposites: one exposing something that is hidden and the other keeping something hidden that should be exposed.  “Out on the table” might also be in the mix.

As any loyal malaphors.com follower knows, idioms involving elephants are frequently mixed.  Type in “elephant” and see the many posts.  There is also a chapter in my book, “He Smokes Like a Fish and other Malaphors” (Amazon) devoted to elephants.  A big thanks to John Costello for hearing this one and sharing it.  Also a big thanks to Cheryl Rosato for her “elephant in the room” drawing and for illustrating the malaphor book!