[Well, she's not wrong in thinking that - the vast majority of Sebastian's actions can be attributed to his proper British butler thing.
Were she to express that concern about being separated by the petals, or look like she's struggling in the wind he'd offer her his arm, but for now, he simply gives her a reassuring - cheerful, even - smile before setting a reasonable pace, seemingly unbothered save for the hand he holds up to shield his eyes.]