This gentleman has a website with muletiple "Drose" videos http://www.josleys.com/show_gallery.php?galid=291

To be fair, while most "no photos allowed" area are ridiculous and unnecessary (Areas in Chicago come to mind.).
Others have a very valid reasons. Some ancient paintings can be slowly destroyed by constant flash photography (much like leaving the works out in the sun will destroy them.) and people are often too inconsiderate or inattentive to take pictures without their flash.

For those of you unfamiliar with Two Girls One Cup, or any shock video for that matter, start with urban dictionary:

http://www.urbandictionary.com/define.php?term=two+girls+one+cup

Urban dictionary is a great way to check whether or not you want to see something.
Like:

http://www.urbandictionary.com/define.php?term=tub+girl

Or

http://www.urbandictionary.com/define.php?term=pain+olympics

Referring to this site first will save your sanity. I have never seen 2 girls 1 cup, and for that I am thankful.