User blog comment:Kaido King of the Beasts/Chapter 818: Stepping Stones to One Piece/@comment-24442815-20160303163252/@comment-24850639-20160303185148

They're indestructible, remember? (assuming the same logic holds for the red ones)

But yeah, Shanks and/or the Whitebeards have gotta KNOW something. We know Roger spilled all the beans to Whitebeard before he passed, and Shanks would have most likely been a member of the crew when the original expedition happened. Even if Roger may have prevented Shanks from going for whatever reason once they actually got there, I'm sure he was still a part of the knowledge sharing necessary to get there. And even then there's still Rayleigh. We knew Rayleigh knows everything though, Luffy just didn't let him spill it at the time. But yeah, the fact that poneglyphs can be copied definitely changes the game.