The elite police and soldiers who practice like this WILL be in situations that the training prepares them for. The vast majority of the rest of us will not. Not only that, the guys who need to train like this devote their lives to training. The rest of us, no matter how good our intentions, will not and can not be trained to the same level, making exercises like this much more dangerous for us than for the warriors.
You sure made a lot of (incorrect) assumptions. Just b/c you dont go out looking for trouble doesnt mean it wont come to you. Being well prepared is just common snese.