I'm completely horrified at the idea of carrying blanks in a defensive gun. What if you think you're shooting a blank when you aren't? What if you think you're shooting a live round, when you aren't? What if you need your first round to be a live round?

As UncleGoo says you can choose to put a live round into the dirt, if your plan is to try to convince the bear that you are not food. This strikes me as a much better idea. For me, I carry a pistol loaded with live rounds and bear spray.