You do not know that, and supposing such, you do not know who they are. Preaching a false gospel to them, for whom Christ didn't die. That would make it evil.
Jesus did not think as you are trying to do;
Acts18;
7 And he departed thence, and entered into a certain man's house, named Justus, one that worshipped God, whose house joined hard to the synagogue.
8 And Crispus, the chief ruler of the synagogue, believed on the Lord with all his house; and many of the Corinthians hearing believed, and were baptized.
9 Then spake the Lord to Paul in the night by a vision, Be not afraid, but speak, and hold not thy peace:
10 For I am with thee, and no man shall set on thee to hurt thee:
for I have much people in this city.
11 And he continued there a year and six months, teaching the word of God among them.
God knew who He died to save, He knew that He had much people there...so He had Paul continue....He did not tell Paul who they were but rather continue to preach and teach.