Originally Posted by christos200
I guess they were too focused on each other and had a false impression of the Liu forces as untrained peasants, to notice them.
Ain't gonna happen. Watch the original 300 Spartans (Done back in 1962) http://viooz.co/movies/9371-the-300-spartans-1962.html
where the scouts saw the Spartans, and reported that they were sharpening their weapons and braiding their hair. Xerxes assumed they were just screwing around. Demaratus, the deposed king of Sparta told him he was wrong. That the Spartans were ready to fight even if Greece did not.
Assuming an even remotely competent observer (Try about a month of training) they are not going to take armed warriors with cavalry as a bunch of ill trained peasants.