Interpreter in training, actually. I hope to graduate this fall.
It depends on how they became an interpreter and what qualifications they have. Understand that not everyone who calls them self an interpreter has received formal training or is even aware that such training is necessary to be an effective interpreter. The program I'm attending emphasizes an understanding of Deaf culture and encourages interaction with the local Deaf community as well as extensive study of ethical decision making.
Then, of course, there are those who have received such training and still conduct themselves poorly because, well, some people are just jerks.