Personally, I've never seen any.
And nobody really reacts when I walk around in my sollux shirt.
(Except for my english teacher who asked why I had two written on my shirt. I then explained it was the Gemini symbol and it was funny because I am both a gemini and a twin.
There was much laughing.)
But apparently a friend of mine has met quite a lot of them.
I don't know how she does it.
I keep thinking there are only two readers here in Denmark.