In the teacher's appeal from her own termination decision, the Pennsylvania Commonwealth Court in DiBattista v. McKeesport Area School District (opinion here) noted:
At Co-worker’s arbitration hearing on March 8, 2005, upon learning that District intended to raise this issue during [the teacher's] testimony, [the teacher's] attorney questioned District solicitor, “But what about [the teacher]?” District’s solicitors responded, “[h]ow many times have I got to tell you? I’m not interested in [the teacher].” Moreover, District’s solicitors had already told [the teacher's] attorney at the meeting on March 4, 2005 that this “wasn’t a proceeding that was going to involve filing charges against [the teacher].”Do you see where this is going?
Applying contract principles, the Pennsylvania Commonwealth Court held that the solicitor entered into an "implied agreement" for immunity in exchange for the teacher's testimony. Therefore, the Commonwealth Court reversed an earlier decision upholding the teacher's termination.
For more on this story, check out the Patriot-News: Commonwealth Court Voids Teacher Firing Over Sex in School.