User blog comment:Zolnir/Flaw in Tournament Setup/@comment-5414218-20160317123214/@comment-5414218-20160317133751

The thing is, that would require them to recognise that situation as dangerous, which only lasted for a split-second and then immediately act before she gets sliced up.

Again, even Ozpin couldn't react to the arrow thrown at Amber. And that's Ozpin in a situation where Cinder was expected to appear at anytime. What are Oobleck's or Qrow's chances in a completely unpredictable scenario? Especially considering most don't even know about Pyrrha's semblance, they might not even know that Penny's weapon is wielded via wires(Ruby didn't notice it at first, although it's possible that the more experienced huntsmen do).

Eitherway, my point is, I don't think having a referee would have made any difference in this particular scenarios at least.