Point is that the Church is aware Of the possibility. One happened during the Decian persecution, although the Emperor solved that by taking out one of the Claimants. I think that during the dark time of the 8th and 9th century, squabbling between Roman famiiies led to a shaky situation. Then we have the worst case caused by the Babylonian Captivity where we have three claimants. the papacy is, after all, a historical development, based on the unique position of of Peter and the prestige of true Roman Church. We are told that Linus succeeded Peter but not HOW.
Good point.