If I were X and heard the testimony that S waived P by... I would withdraw my protest (assuming that I could at that point).
A protest can be withdrawn if the protest committee allows (see rule 63.1). I agree that if I were representing boat X, and heard S's and P's stories in the room, I would ask to withdraw the protest. If I were on the protest committee, and X asked to withdraw his protest after hearing the other boats' testimony, I would vote to allow it.
Regards,
Eric
