A reader and podcast listener named Paul Tucker writes to say:
While listening to the "Herd Mentality" podcast piece about the Petrified Forest National Park, I thought you missed a very pertinent display at the park. At the south entrance to the National Park the visitor center has the Rainbow Forest Museum. In the museum there is a room dedicated completely to the theft of petrified wood. It is called the Guilt Room. The room is filled with pieces of petrified wood and the packages they arrived in and their accompanying letters of remorse and contrition by people who are trying to assuage their guilt by returning the offensive fossils.