[c_of_red]

Not sure what the question is. There are factors that reduce a units ability to successfully search for an enemy. I don't remember them all, since the computer handles that for me. Most are common sense anyway. Sitting units search better then moving ones, moving units are easier to see then ones sitting behind a bush. Big ones are easier to see then little ones.
Experience and suppression count too. Vision ratings, etc.
Shooting units are easier to see also.