Timothy Robicheaux and Brian Bornstein have an intriguing review of appellate cases in the current issue of Psychology, Public Policy and Law (abstract free, full article behind pay wall). About three fourths of the time, appellate courts have followed the principal of criminal law when dealing with punitive damages, i.e., there is no point in punishing the dead.
However, in a minority of cases juries have decided and appellate judges have concurred that such awards are appropriate. The rationale is that even though retribution is impossible, punitive damages against a deceased defendant’s estate deters other potential offenders. The type of case most likely to result in upheld punitive judgments against the dead are those involving auto accidents (e.g. cases in which an intoxicated driver died while injuring or killing others).