I learned to ride extremely defensively. I unclip one foot at the slightest provocation (yellow traffic light, gravel ahead, ruts, kids messing around, etc.). In eight years and 25,000+ miles in clipless (my other two bikes have toe straps) , I have never fallen in a "traffic" situation or even one resembling one. In fact, I have only fallen 4 times, period, and the last two had nothing to do with clipless (the first two were my obligatory "learn clipless" falls). I think you are more likely to fall while clipped in on a MUP than in traffic.
I guess it doesn't rate as a very big worry for me. I do think the clipless help in a traffic situation, as I can accelerate markedly faster on the clipless than on pedals, as I can use the "upstroke" to really get moving. YMMV.