They've done this in the past. Its always gotten scrapped because the fighter announced winning can very easily play keep away and refuse to engage if he knows for certain he has a lead. This is just a bad idea for fights that are fought competively. In many instances a really good competitive fight will have a fighter up 3 and even 4 rounds heading into the championship rounds. .....then we get the fighter up on the cards playing keep away and totally disrupting what was a great fight.
Yep. Open scoring is shitty and just like divac stated - if someone is up on the cards, they'll just stay away.