All attempts to negotiate or compromise cannot be offered in court as proof of liability.
Rule 408. Compromise and Offers to Compromise
(a) Prohibited uses.—Evidence of the following is not admissible on behalf of any party, when offered to prove liability for, invalidity of, or amount of a claim that was disputed as to validity or amount, or to impeach through a prior inconsistent statement or contradiction:
(1) furnishing or offering or promising to furnish or accepting or offering or promising to accept a valuable consideration in compromising or attempting to compromise the claim
Those are the Federal rules. They vary from state to state, but most are pretty close.
Rule 408. Compromise and Offers to Compromise
(a) Prohibited uses.—Evidence of the following is not admissible on behalf of any party, when offered to prove liability for, invalidity of, or amount of a claim that was disputed as to validity or amount, or to impeach through a prior inconsistent statement or contradiction:
(1) furnishing or offering or promising to furnish or accepting or offering or promising to accept a valuable consideration in compromising or attempting to compromise the claim
Those are the Federal rules. They vary from state to state, but most are pretty close.