i think her face expresses what she is really feeling; as her face expressions pretty well match whats going on... and in someways not whats going on... for example, when eric was talking before he was voted out; she looked like he was full of crap... which he was; but not from the standpoint of saying that he was... but more from the standpoint of what he was saying....i dont know,

but i dont think the facial expressions are for show... i think they reflect what eliza is feeling.