Well, it seems to me that it comes down to the issue of "reasonable expectation of privacy".
The FBI is allowed to eves-drop on the conversations of gangsters without a warrent if they are talking outside in a park or while walking down the street. The justification is there is no "reasonable expectation of privacy" in that setting.
If the video has been shot inside her serority house, or even the backyard of the serority house it might be different. I can't believe that even twelve Oprah watching, slack-jawed mouth breathers could decide that someone exposing herself in a crowd of several thousand people, on a public street, could then claim any "reasonable expectation of privacy".
IMHO.
Regards,
Wab