Legal Question in Civil Litigation in California

The attorney can suggest it, and the client can reject it. If there is a subpoena in a later case, the client and/or his/her attorney would then have to meet and confer with the subpoenaing party and the settling defendant to discuss the issue, and perhaps have the court resolve whether the client must appear under subpoena. In addition, the defendant in the settled case should also be notified because the client would not want the settlement agreement to be violated.

Typically, settlement agreements should include the words "voluntarily appear," and except such provision on service of legal process or subpoena.

I think that such an agreement is inappropriate and unethical when suggested by an attorney, because it would constitute suppression of evidence. "A member shall not suppress any evidence that the member or the member's client has a legal obligation to reveal or to produce." (Cal. Rules of Prof. Conduct, rule 5-220.)

I also think that it would get a client in trouble, who would disobey a subpoena just to comply with a settlement agreement. I don't think a settlement agreement would be a viable defense to disobedience of a subpoena.