There is a site called streaking.org that is probably the 'mainstay' of any centralized and focused group for people who like to streak. If you're thinking there will be lots of hot pictures of streakers there, you'll be disappointed, there are none; it's mainly just a discussion board for streaking.
One of their precepts is, they are quite adamant about streaking being the 'non sexual act of taking off one's clothes and running naked through a public place.' If you've read my post on non-sexual nudity, then you will realize that I have a very different point of view from their ideology.
I do agree a streak shouldn't turn into a jack-off session, but I don't care how you look at it, the desire to run naked through a public place gives some amount of erotic pleasurable energy to the person doing it. It may not be overt, such as getting an erection; but the idea of streaking transcends simply being nude. There is a vast difference between enjoying non-sexual nudism, by going to a nude beach, and publicly displaying yourself naked by running through a crowd. I do agree it is non-sexual, by my definition, but not by theirs. In fact, if you read their discussion board, they literally blast any guy who happens to get erect during a streak.
For a group of people who want to express themselves in such a way and achieve some level of acceptance, they appear to me to be pretty opinionated and closed-minded. It's fun, it's naked, it provides pleasure and excitement -- so whats the big deal if it is mentally sexual or not?
If you read about my idea of a streak it's similar but not identical to their ideals. I disagree with the whole 'purity' concept of locking someone into another persons idea of what something is or should be. Streaking is about the desire to harmlessly showoff your naked body to a group of people quickly for some level of surprise and shock value.
. . . Matt