Mistake of Fact – Jury May Consider Reasonableness of Belief on the Issue of Good Faith
It is well established that a good faith mistake of fact can negate specific mental state elements of a charge such as knowledge. (See People v. Watt (2014) 229 Cal. App. 4th 1215, 1217-1220; People v. Lawson (2013) 215 Cal.App.4th 108, 115. Thus, the Bench Notes to CC 3406 read, in pertinent part, “If the mental state … at issue is … knowledge, do not use the … language requiring the belief to be reasonable.”
However, the issue of reasonableness may still be relevant on the question of good faith:
In determining if a mistake of fact has negated a specific mental state, the jury may consider reasonableness in deciding if the belief was in good faith—a highly unreasonable belief can support an inference of bad faith, so while objective reasonableness is not a requirement of the defense of mistake, subjective reasonableness can be a relevant consideration on the subject of good faith. [Citations.] (Watt at 1218.)
And, if a highly unreasonable belief can support an inference of bad faith it follows that a highly reasonable belief can support an inference of good faith.