Mark 2:15ff: And as he sat at dinner in Levi's house, many tax collectors and sinners were also sitting with Jesus and his disciples--for there were many who followed him. When the scribes of the Pharisees saw that he was eating with sinners and tax collectors, they said to his disciples, "Why does he eat with tax collectors and sinners?" When Jesus heard this, he said to them, "Those who are well have no need of a physician, but those who are sick; I have come to call not the righteous but sinners."
14:18ff: And when they had taken their places and were eating, Jesus said, "Truly I tell you, one of you will betray me, one who is eating with me." They began to be distressed and to say to him one after another, "Surely, not I?" He said to them, "It is one of the twelve, one who is dipping bread into the bowl with me.
This is in blatant contradiction with Paul's recommendation. And if (as I believe) this picture of Jesus eating with sinners and not shunning anyone (even Judas!) is a literary construction by Hellenistic Christian communities, it is all the more amazing that it goes against the Pauline restrictions.
So I guess the question "Paul or Jesus?" (as Jez put it in the other thread) stands, even if the choice involves a literary construction -- perhaps two?