Bradford got lucky in that it didn't result in a nasty injury. Just as lucky was Burnett, who got away with attempted murder while the refs stood idly by. Check out the video evidence:
Inexcusable. The refs gave the Rams a makeup call, but that would have been little consolation had the Rams lost their starting QB on the kind of hits refs are responsible for taking out of the game.
Burnett ought to get a hefty fine for this, but is he the only one that should be punished? Doug Farrar makes a great case in this post at Shutdown Corner for how to handle these kind of hits. Fines and suspension for refs should be part of the answer. Will at Rams Herd has a good post on this too.
It's one thing to watch when your team doesn't get a pass interference call. This is different. Teams invest too much money in personnel and fans invest too much time and money of their own to watch top players get taken out because of referee idleness.