The problem is that the vest is a Pain in the ### to deal with when wearing rain gear or a parka. All of the jackets that we have issued, already have a reflective stipe on them anyway. If you can't spot a guy wearing a bright Yellow rain jacket, you should be travleing with a seeing eye dog to begin with.
I'd like to shed some light on a few of the points you just made in your post. First, If you are wearing a Company issued yellow rain parka with a reflective stripe, you need not wear a vest. Secondly, from my understanding, it is necessary to wear a reflective safety vest during R+D functions as a federal regulation. The color need not matter to the feds, just the fact that you wear one during R+D functions, the orange color is just the color that USAirways has chosen for us to use. Remember, a lot of the things we do for safety on the ramp, go hand in hand with some sort of federal aviation regulation.