"He should have armed himself."
Funny that you should pick that quote. (by the way, I stopped to post a response upon reading this post, so if this has been addressed, I will come back and edit this). The rest of that line is "...if he was going to decorate his saloon with my friend." He didn't shoot the man because he was unarmed, but because he put the corpse of eastwood's friend up in front of his saloon. Also funny because the whole premise of this movie was two men going up to take revenge upon a man who beat up an innocent woman. Of course, she was a prostitute, so I'm sure that excludes her from the "save-worthy" category that some of the posters in this thread seem to have.
Here are the questions that go through my head. I will not demand that you think them yourself, however.
1. Is what's going on here right or wrong?
2. If wrong, how can I help to stop it?
3. How can I help to stop it with least risk to myself and others?
Now, the thought of self preservation is an obvious component of these questions. I cannot help if I am dead. I also could possibly make things worse for myself and others involved. If all I can do is witness, so be it. But I will determine that myself, not based upon someone else's decision making criteria.
I find it somewhat ludicrous that those who would uphold what is right and good regardless of personal expense must defend themselves and their decisions. If you won't do it, I have absolutely no problem with that. I do not think less of you, no matter your reasons, be they what happens to your family if you die or simple fear or whatever. I will however intervene in the best way I deem possible to stop the wrong, for anyone.
This is a general principle that is obviously open to situational evaluation. But at my core is a white pulse that says "I will do what's right and stop those doing wrong."