How would a random Priest at a mass Mass know for certain the disposition of the soul of a communicant?
He wouldn't; I'm not talking about this particular Mass but priests who KNOW their parishioners WOULD KNOW who are divorced and remarried without an annulment!
Now about my initial queston? Was Rudy not supposed to receive Holy Communion or have the rules changed? Or did Rudy commit a mortal sin?
He can't. However, in the case where he is aware of a potential problem, such as with Julie Annie's very public situation, the priest can ask if he's been squared away before offering it to him.