These ancient policies manage to survive due to the huge homogeneity of our population which makes it hard to challenge. I'm pretty sure that Jesus would spin in his grave if he knew that the Finnish state is collecting taxes for the church.
That kind of policy was pretty common in the 50's. Phillips had a policy that women should resign once they got married.
....and anyone can check your income by doing so much as sending an SMS.
Its worse then that, when I google my name it returns links to the newspaper articles that publish huge lists of people and their income every year. Maybe with the recent first real kidnapping for ransom they'll start to reconsider that.