Paul, here is more info to convince you that the Guinness World Records Organization will have a catagory
How many people do you think can simultaneously skinny-dip across North America? Guinness World Records organization has agreed to create a new category for the largest number of people simultaneously skinny-dipping, and AANR is the contact association for this record event. AANR plans to coordinate skinny-dipping events at participating clubs and legally-sanctioned nude beaches throughout North America on Saturday July 11, 2009 at 3:00 p.m. Eastern Nudist Time, to coincide with Nude Recreation Week.