I can only guess this player isn't rotating the pieces because he's afraid he might touch the cosplayer's nipple. Or that he'd like it.
I go to Ohayocon (anime convention) sometimes (I went last year, but not this year), usually to shop. Pretty fun. A few years ago I saw a couple there who were dressed as interlocking pieces from Tetris (weird).
Weirdest thing I recall was when I took a niece to the show (This was around 2003 or 4) and a college-aged girl from a table, dressed as the catgirl from Escaflowne, came to us and offered to do anything in exchange for coming to her club's table (I think she also rolled around on the floor, like a cat).
All I can say is I wished I had came to the show alone ^_^. Nah. My niece and I had a great time, despite the offer...snif o_<