Here's one the California Supreme Court got right in December (and frankly I admire the court's willingness to change its mind): In 1994 the State Supreme Court ruled that if a juvenile is searched via a search that would otherwise be illegal, the search would be permissible if, after the search, the police were to discover that the juvenile was on probation.
This made no sense in 1994 and fortunately in 2006, the State Supreme Court decided to do something about its previous erroneous decision. If a search is improper, it is improper. Why should it matter if, after the search is done, the officers happen to learn that the juvenile who was searched was on probation? That doesn't make it right.
Well, the bad decision of 12 years ago is now erased by a 6-to-1 vote, with the State Supreme Court acknowledging being influenced by intervening court rulings and "strong scholarly criticism."