Not much has been said about this but Azekiel summed it up nicely what it means to be a Vindicator.

Two thousand years ago, a Roman citizen could walk across the face of the known world free of the fear of molestation. He could walk across the earth unharmed, cloaked only in the protection of the words "Civis Romanus" - "i am a Roman Citizen" so great was the retribution of Rome, universally understood as Certain should any harm befall even one of its citizens.

I am a member of the Vindicators.