I have known people who bought pilot jackets complete with house "flight patches" for battletech. Or Race car driver jackets for 50 bucks to play a game called Stock Car Championship. None of these guys are roleplayers, just more or less wargamers. I used to know a woman who played morrow project with a complete green coveralls suit with all the appropriate Morrow Project patches and a airsoft .45 on her hip. Cowboy hats in various colors to play Boot hill. Dark or Mirror shades and leather long coat duster jackets for cyberpunk. And most of us are old school. When I GM a modern military game, I wear my desert storm field shirt, and a chocolate chips camo do-rag. We use walkie talkies. Many would say, yeah too much. When I played Vampire, I wore a silk cape, fangs powdered wig the whole bit that my then girlfriend a film costumer arranged / made, rigged up for me. I added a sash with russian medals (A tremere from da olt country.) It's fun. When I GM D&D, I wear a "I'm the DM" t-shirt. Traveller, I wear my 25th anniversary of Traveller woolen knit shirt.