hmm i have routed on purpose once or twice, it can be very effective for getting enemies right where you want them,

a good example (online) is when i was defending on a map with trees on each side at clear centre and no hills anywhere (hard to describe) i hid men in both side of the trees, and then put quite a few men in centre to make it not quite as obvious that i had men in trees. He wasnt going to fall for it though and just stood there shooting my inf and pavs, so i charged that half of my army right at him, and after maybe 30 secs routed them, they ran straight down centre, and he couldnt stop men chasing so i hit him on both flanks with my best units, the runners then rallied and i crushed him