Star Wars: Rogue One - 11 Things You Might've Missed In The Official Trailer
9. Bodhi Rook's Imperial Insignia
Imperial insignia is clearly the latest trend if you're working for the Rebellion. Earlier in the trailer we see it on Alan Tudyk's mo-cap droid, K-2SO (Kaytoo? Kaytooso?), and then we see it again on the arm of Riz Ahmed's Bodhi Rook.
An inhabitant of Jedha, he was conscripted into the Empire as a pilot, something he went along with for a while before gradually realising the horrible things he was being asked to do, and defecting to the Rebels. Now he wears the insignia on his arm as a reminder of his past.
It's a similar setup with Kaytoo, who is an enforcer droid created to serve in the army, but was reprogrammed by Cassian Andor (although he doesn't have as much choice about wearing it).