I think the logic is that seastone prevents DF users from actively using their power. Luffy's ability is a passive ability, he does not have to transform into his element like Jozu or logia users. That's why Luffy can be stretched when cuffed by seastone.
As for Doffy, I don't think material produced by producer types dissappear after the user is KO. Like how ice produced by Aokiji won't dissappear when Aokiji sleeps.
Birdcage dissappeared because it is an active usage of his ability, but his stitches are simply strings which are just products of his DF.
At least that's how I think it works.
As for Doffy, I don't think material produced by producer types dissappear after the user is KO. Like how ice produced by Aokiji won't dissappear when Aokiji sleeps.
Birdcage dissappeared because it is an active usage of his ability, but his stitches are simply strings which are just products of his DF.
At least that's how I think it works.
Marco couldn't heal while cuffed, but that's not passive
I do agree that Doffy's strings wouldn't disappear, but maintaining them seems necessary if logic were applied