Signing clothes, increasing visibility, being put to use

Police, firefighters, ministers and agencies staff all had some clear markings on their clothes, usually the back of the overcoat, telling what they were and giving them authority. We, a bunch of volunteers had none, except a small paper badges in plastic hanging from the neck. I am looking now in Tokyo for services to mark some essential overcoat I might be using again, to tell the world around my role, increase visibility that would lead to a better usage of services in situ interpreters can offer granted they are identified as interpreters.