It is not uncommon for the defense in personal injury cases to attack the character of the plaintiff. It seems to me that young defense lawyers particularly enjoy doing this to uneducated, unsophisticated plaintiffs.
The defense in a products case in California introduced evidence that the plaintiff had a mistress and was a bigamist. The jury rendered a defense verdict, and the plaintiff moved to set it aside saying that the admission of the evidence unfairly prejudiced the jury against the plaintiff. The California Court of Appeals, 2nd District agreed, saying
Michelin’s primary basis for introducing evidence of Winfred’s illicit conduct was to contradict his deposition testimony that he could not recall who [his wife and mistress] were. But his extramarital affairs were irrelevant to the substantive issue in the case: the cause of the accident. To the extent the evidence was relevant to Winfred’s credibility, it was more prejudicial than probative. … From start to finish, Michelin painted Winfred as a liar, cheater, womanizer, and a man of low morals based principally, if not solely, on what we have concluded was inadmissible evidence.