I have but I went at the wrong time of year. I went in the summer so I could't use my excuss and say - its just shrinkage because it is cold outside. Cheers!
Our church youth group was taking a white-water rafting trip down the Deschutes River, in Oregon. I guess one of the small beaches along the way is "clothing optional". Our raft had to put in to repair a small hole, and that was the closest beach our guide could get to.
Many times I have been to clothing optional Wreck Beach right within the city here. During the heat of summer days there may be as many as 6000 people getting their buns suntanned. It is a popular tourist attraction.