>>106238057If he Ping would really cause more problems than he would be as use for cannon fodder yes. Mind given the circumstances Ping would have to a been way worse than what was shown for that to have happened.
All that being said and done Shang was a very strict officer with his first ever command, it's entirely possible he simply had not considered that as a possibility, or much more likely didn't realise the severity of the war. The last point in particular is hard to fault him on, he had just been told by his father and his general that while it was a serious war he wasn't pressed for troops or anything, so Shang would be justified in feeling he could send some particularly undesirable soldiers back.