Does the Retired Pope Have Legal Immunity?

It's a question that has not come up for almost 600 years (and legal immunity back then probably just meant having the better army), but an attorney for the Vatican has the answer: yes. So why would a retired pope need immunity, anyway? According to this ABA Journal story, the global priest sex scandal poses legal risks. Duquesne law professor and canon lawyer Nicholas Cafardi told AP that he is concerned about action against the retired pope if he travels, especially in Europe where magistrates can arrest and detain officials before trial.