Someone said if Yamato want to attack Kaido, but Luffy said "Its not us who gonna start the war", and then we saw Nine Red Scabbards attack Kaido.
Luffy probably saw the scabbards invading with his FS, I am assuming... and I also think Luffy realized that Scabbards MUST BE the ones who make the first move as a declaration of war
Even jinbe told Robin that back then when he said that they should wait for the Samurai to make the first move..
I think it's obvious that Oda is keeping the Strawhats AWAY from the higlight of this stage (Luffy is with Yamato away/ Zoro is with gifters/ Sanji missing/ Jinbe and Robin inflitrating/ Chopper and Usopp are doing their own thing/ Franky and Brook doing their own thing) Only Nami is there in stage, but we all know she'll be free very soon.. so
I think it's obvious that Oda is keeping the "MAIN POWERHOUSES" away from the stage... EVEN MARCO... and he intends to hand this big L to the Red Scabbard in next chapter or two I'm assuming... before the other fighters barging in
I think Oda intentionally avoided Marco being there so that he doesn't join the early casualties from Scabbards