I think it's complicated. I do try to be respectful enough to sign if there's a deaf person within the area, however sim-comming is not effective in any decent conversation. Also, if the person i'm talking to is hearing and can't sign, the question would turn into do I start interpreting for them, or would the deaf person just be able to see one side of the conversation? I shoudn't have to be in interpreter mode in a casual setting.
For the record, i'm an interpreter, i'm hearing, and i'm a coda.