The Pennsylvania Supreme Court has held where an agreement clearly allies two or more parties against another, such that a clear potential exists which would not otherwise be apparent to the factfinder, that part of the agreement, or at least the existence of the reason for the potential bias, must be conveyed to the factfinder.
Hatfield v Continental Imports, Inc., 530 Pa 551, 610 A2d 446 (1992).
Barbara S. Campbell,
Civil Procedure - Admissibility of Settlement Agreements - 42 Pa Cons Stat Ann § 6141 - "Mary Carter" Agreements,
Duq. L. Rev.
Available at: https://dsc.duq.edu/dlr/vol31/iss4/12