In a recent question, Fr. Serpa said that annulments are not protected by infallibility. This makes sense to me but it raises the question of whether or not someone who has a marriage declared null and remarries could unknowingly commit adultery if the declaration of nullity is in error. It stands to reason that some annulments would be in error, whether because of honest mistakes or dishonesty on the part of those seeking the annulment. If an annulment is in error because of honest mistakes and the person recieving the annulment remarries, would he or she be culpable for adultery? Also, could it be that the Church’s God-given authority to bind and loose would make such errors irrelevant?
On a related note, why are the positve declarations of canonization infallible but not those of nullity? What separates the two types of declarations? Is it those who make the declarations, i.e. bishops v. diocesan tribunals?