As far as the collection of taxes was concerned, the official responsible to Rome during the time of Jesus, would have been Herod Antipas for Galilee and Peraea. Matthew would have been one of Herod’s agents. In matters dealing with Judea and Samaria, the official agent responsible to Rome for collecting taxes would have been either Pilate or the president of Syria, and Zacchaeus would have been one of his agents. It seems, however, that the text places a greater responsibility upon Zacchaeus than upon Matthew, who may have been responsible for only a specific location in or near Capernaum. Zacchaeus, on the other hand, seems to have been the taxing authority in Jericho, and, no doubt, he had other taxing agents working under his authority. These agents would have been responsible to him, but he was responsible to the Roman authority accountable for collecting taxes for Rome.
In Jesus’ parable the nobleman’s servants are similar to those who conduct affairs as a businessmen and / or tax-collectors. They are not like those having military authority. Nevertheless, the nobleman in the parable, if he gained a kingdom when he went to the far country, would have had a ready military at his disposal, just as Herod Antipas and the Roman procurators had.
From Luke 15:1-2 and Luke 19:2 we are able to conclude that publicans and especially Zacchaeus, because he was a chief publican, were hated by the Jewish people. Moreover, if we take Luke 19:14 into consideration, we can conclude that the nobleman and Zacchaeus had something in common. Both he and the nobleman in the parable were hated by the people over whom they were in authority.
Jesus claimed that his disciples would be treated just as he had been treated (Matthew 5:11; 10:22; John 15:20). If people hated Jesus, they would hate his disciples. If they persecuted Jesus and sought to slay him, people would seek to do similarly to his disciples. Jesus confronted the Pharisees and rabbis of his day about many things, challenging their authority to do as they were doing among the Jews. They often considered his behavior unacceptable, according to the customs of that day, and they hated him enough to try to kill him (cf. Mark 3:6; 12:13).
Zacchaeus did that which was thought to be unlawful among the Jews. Most Jews assumed it wasn’t lawful to willingly pay taxes to Caesar (cf. Matthew 22:15-17). They considered themselves autonomous, owing loyalty only to God (cf. John 8:33). Therefore, they considered it extortion for someone like Zacchaeus to enforce tax or custom payments to a foreign government.
Moreover, publicans often extorted more from the people than was fair (cf. Luke 3:12-13), but the people had no recourse but to pay, because publicans had the Roman military at their disposal to make sure their fees were met, if problems developed. No doubt it was for these very reasons that publicans, and, therefore, Zacchaeus, are often mentioned in the New Testament with sinners (Matthew 9:10-11; Mark 2:15-16; Luke 7:34) and even heathens (Matthew 18:17). Additionally, they were considered ceremonially unclean due to their frequent contact with the heathen, and their being willing accomplices of the Roman tyrant. They were all but excommunicated from Jewish society, and were not permitted to be judges or even witnesses. Even their families suffered ostracism due to their chosen vocation. Thus, the similarity between Zacchaeus (publicans) and Jesus and his disciples becomes apparent in this parable.
 In Levi’s (Matthew’s) case, because he operated in Capernaum of Galilee, enforcement was secured through Herod Antipas’ military.
 Babylonian Talmud, Sanhedrin 25b.
 See Babylonian Talmud, Shevuoth 39a, which claims tax-collectors’ families were incriminated with them, because it was assumed they protected them.