Confidentiality
As the previous examples show, interpreters are privy to very private information about their deaf clients. They may hear that the person has HIV or is being sued, for example. For this reason, deaf clients must not only have confidence in their interpreters, they must trust the interpreters not to blab their personal business.

The deaf community is often like a small town where gossip spreads like wildfire. An interpreter needs to know how to keep his or her mouth shut. The relationship between a deaf person and a sign language interpreter is a deep trust that must not be violated.

http://carolafinch.hubpages.com/hub/Characteristics-of-Effective-Sign-Language-Interpreters 11092015