I was serious, lmao.
How do you think Gorosei knew Luffy awakened?!
Think Litm, think.
It's actually just "think Litm" not "think Litm, think"
and I refuse to believe you were serious. As for the answer I don't know how they knew he would awaken, either Oda explains it later or it's just another plot inconsistency, it wouldn't be the first time
After all some characters awakened off panel, forgot they had CoC coating or were able to use CoC coating without even knowing they had CoC. Didn't see their fandom crying about that