"Kaito-san did? I guess that makes sense, he is very kind.." And also apparently didn't go in the water! (It'd help if she knew about his aversion to fish, then she'd immediately knows the reason for it..) The more important point though is definitely that he's nice, because Madoka really thinks that.

"W.. Well, then next time you get seasick I'll help you out too, mister Gladio!"