It's happened twice already. She doesn't like it. She won't follow suit and whip out her breasts. Those are part of her work uniform. Still want to date Rhian? Learn about her thoughts and feelings in Loaded.
Really, gents, in what world is flashing an appropriate way to approach a lady? Just because you happen to see Rhian topless 99% of the time doesn't mean you can inflict your naughty bits on the 1% of clothed existence she has. On another level, this might actually make an interesting survey for lad mag babes: "How many times have you been flashed in public?"