Simply put: No.
Vitor Belfort is a passionate fighter, overly perhaps, and it's often hard to contain such zeal when you are attempting to end the night of your opponent inside a cage built for combat. But that doesn't give Belfort, or any fighter, carte blanche to engage in reckless abandon.
So what does a referee to do?
Should Belfort have been disqualified? Probably not. Should a fighter have a portion of their paycheck deducted? Perhaps. But, in fact, the opposite happened last night as Belfort was awarded with a $70,000 bonus for his Knockout of the Night performance.
Sometimes good things happen to passionate people who "inadvertently" do something "bad."
Fighter safety is paramount of course; they shouldn't have to live in fear when it comes to defending against illegal blows.
While shots to the back of head have not become the headache to the sport that, say, bad judging has, it is a serious issue that needs to be nipped in the bud before it has the chance to get unruly.