Because hopefully CIG thought this out and since murdering a downed/helpless person is now a distinct, intentional act, the penalty will be modified. Ideally, now you will get a DAYS long prison sentence and lose tons of reputation for murdering a helpless person, just like you should if you shoot an escape pod or ejected pilot. This will open up gameplay for criminals to use downed combatants as bait, or fight off medics from approaching the wounded. With the modified penalty, downed state isn't just a slightly delayed free kill.