Back in those bad ol' middle ages people actually feared for their souls, including princes and kings, and the excommunicated would do public penance and the interdiction would be lifted.
In our enlightened age the church wouldn't dare try excommunication or interdiction for fear the people wouldn't miss the sacraments.
Thanks for the post and ping. You're right, of course, that at one time, people feared for their immortal souls. Enlightenment, as you also point out, has supposedly 'liberated' them. Or has it? A while back, our pastor was making rounds at a local hospital. He stopped by the bed of a retired politician. He told the priest he had just learned that he was dying and would the priest hear his confession. While the priest did not reveal the content, he apparently repented of some of his political stances.
Today a young woman called the rectory looking for an RCIA class. Apparently, she was baptized but never made any other sacraments. She wants to get married in a catholic church and was told she must complete that program before so doing.
Even the enlightened, it seems, have consciences ;-) We need to pray that they will not only repent and study but also apply these teachings to their own lives and return to the church.