Well so McCain has said that he had the same experience that Solzhenitsyn had when someone drew a cross in the dirt (sand, snow, whatever) while they were both prisoners. Of course McCain doesn't want you to think that he would ever mention his POW status for mere political purposes. It could have happened. On the other hand he didn't mention it for 25 years after he was released.
You know I think that the real thing here is that McCain (an any Republican) can lie as much as they want while Democrats can't mildly exaggerate the truth.
A final thought. I've seen stories about Solzhenitsyn having that experience, but I haven't seen any which either links or purports to send one to the actually page and book that the story came from, if it is really from Solzhenitsyn and not some glurge made up after the guy died.