In the pool room, Sam says "Swear to God, my very first time, was in the 6th grade, school crossing guard." This contradicts what Sam said in Don Juan Is Hell (1985), when Diane is doing a case study on Sam. He says, "I know I couldn't get to her house, until the crossing guard showed up." Diane asked about his second encounter, to which Sam replies, "That would be the crossing guard."
As a trained psychiatrist, Frasier would know about patient confidentiality. Therefore, he wouldn't point out in front of the others that he is seeing Karen. He would act like he didn't know her and confront her about what happened in their next session.