even though this thread should be over, i thought of a similar scenario: same situation as the op, but the thrower(p1) plays from/picks up the wrong disc as his own (looks identical) & puts in his bag. the other thrower (p2) can't find their disc & declares their disc lost then plays from their previous lie (+1stroke). then at some point after finishing this hole, p1 finally realizes he's got the wrong disc. by the rules both players get the 2 stroke misplay penalty (
811.f). this seems really unfair to p2 (not only the stroke & distance lost disc penalties, but 2 more for misplay not even their fault). i don't see a way to address this to make it right, it doesn't appear we can use the
fairness rule, though it is unfair that p2 is getting the misplay penalty. maybe with an appeal the td could use
801.03d & have p2 replay the hole; it does appear there has to be an incorrect interpretation of the rules for 801.03d to happen and i think i have the interpreted & applied the rules correctly.