1. What if I am wrong?
2. How will they respond?
Answer:
2 Corinthians 5:21
He became since that we may be made the righteousness of God.
Proceeding from this simple basis, then let the Spirit lead one where one must.
Do not be afraid to speak the truth. Be afraid, rather to let the truth give way to convenience and immediate custom.
Better to challenge and be corrected (always confident that one's standing in Christ can never be compromised) that to compromise one's peace tolerating someone else's fraud.