The same argument could be applied to Christian priests in rural parishes too. I'm sure they were easily distinguishable though through their vestments.What I would ask is: did they need to have a sign of their office? Communities being smaller, would not everyone really just know who the local druid was?
I also subscribe to Oppenheimer and Cunliffe's theories in that the word Celtic could be better applied to a Culture that specific groupings of people.[condensed by Dysgwr]... genetic history work of Stephen Oppenheimer on the Origins of the British. ... Which is what Professor Barry Cunliffe suggests, that what are now called the 'Insular Celts', which provides the roots to Druidry, were formed from an Atlantic Celtic culture that had it's own sophisticated spiritual continuum.
Caesar's writing must be handled with care.. He was writing for a specific audience selling his invasion of Britain. A good seeling point was saying that britain was the crade of the barbaric religion which used human sacrifices to appease its Gods. It is not know that Caesar knew about Stonehenge or and Celts from that time which which he had contact knew about the megaliths. He could have been aware of the megaliths of Carnac and other places also. But from what I've studied scholars agree that it is probably just propaganda justifying a costly invasion and a means to further his glorySo there's the evidence from Caesar, Strabo & Tacitus for early Druidry - Caesar says that the root of Druidry is in Britain. Earlier Greek writers and the archaeological history, included Stonehenge, suggest a religious centre in the British Isles.