Post Praetorian said:

To clarify, if the assumption may be that each might make a logical and fair claim to a given system of belief absent any central organizational oversight or indoctrination, how might the individual riding among them know whether she should be wearing a scarf in the presence of one, hiding ornaments from another, remaining relatively at ease with one, while ensuring she is not left alone with the last?

We could really go around this maypole forever. At this point, I could ask how does anyone make a decision at all when faced with a situation not clearly covered in the Bible? By weighing whether an action might cause harm to others (or oneself), might help or hinder the world and its creatures - i.e., by using the brains we are so lucky to have. To which you could opine that without a spiritual anchor, one might not even know that it is bad to harm others, to which I could counter that evolution itself breeds cooperation, to which you could point out cruelty among animals, to which I could observe equal (or worse) cruelty among humans, to which... etc. etc. ad infinitem.
At some point, you either decide that you have faith or you don't. I don't.

I never did address your original question, as to whether I might feel more at ease in a dark alley with a Christian or an atheist. Hmm, I'm not sure. Depends on several factors - where I am, what race I am, etc. Me? I'd probably rather bump into a Christian. But if I were wearing a turban and it was in a dark alley in Alabama, I'm not sure I'd want that big burly drunk I bump into in an alley to be a Christian. Actually, I think the question speaks more about our biases than about any actual statistical safety. We all have subconscious biases based on how we were raised, experiences we had growing up, etc. I'm sure I do too.