So, I don't actually know for sure if it's bannable or not. But someone last night at spawn stood next to me and copied my TRP word-for-word to impersonate my profile. They changed their username to 'Tyrannaa' and even went so far as to make a guild similar to my own named 'Guardian's' (While my real guild is named 'Guardians'). They appear to be joining phases.
It's not a huge deal to me but the idea of someone going around pretending to be you and doing whatever, making people think it was you, feels like something that staff would be interested in to me.