Chewbacca is one of he regular attendees at the Motor City Comic Con. I can't be sure it is the same Chewbacca every year, but it looks the same (Chewie never ages).
It is all part of the fun, as people dress in character. Chewie is one of the most popular characters, often being stopped for photo opportunities, like the one below.
I have heard Chewie can be a bit surly, but he never gave me any problems. Last year, he waved for the camera. This year, he was smiling. Of course, if you look to the right side of the picture, you will see we were near the booth featuring Mickie James. That might have been the real reason behind his smile.
JayHawk Evans, Chewbacca and me in Novi, MI-May 2011.