Well I'm sure they are allowed, and if not then people didn't care because:

For one, during a dodgeball tournament over at the U.S. Smokeless tobacco setup behind The Boardwalk there was a guy who decided to run through the area in the same thong/suspender get up that Borat used in his movie. Although the site was not to pleasant, it was quite humorous nonetheless.

For two, on my way back into The Summit from the beach there was a lovely young lady rocking out a white thong. Of the two, this "thong experience" was much better than the first.