Assume you won't be recognized...and then go ahead and do it anyway.
I mean, if people catch on that you're from Code Geass, that's a good start, and the KoR costume is pretty distinctive for that.
Katsucon 2016 Costumes
(Hobbit/Lord of the Rings)
: Curufin Son of Fëanor
...and saving Angel!Trisha (FMA:Brotherhood) for another time
Cons: AnimeUSA '09, AnimeNEXT '08, '09, CostumeCon '09?, Katsucon '08, '10, '14, '15, '16, Otakon '12, DragonCon '15