However, to my real question, I spend some time in the USA and it amazes me how may people have car number plate surrounds or wear caps that say "I fought in Vietnam" or "Ex Marine Corps" etc. (usually followed by "and proud of it"; which I am happy they are entitled to be.)
Surely that sort of blatant advertising is just asking to be a potential target of the ungodly ?
Probably safer than "I work in congress" on your plate.