I think the answer is, it depends. In some situations, a flashing light may attract the person's attention quicker, but that may or may not be desirable. That is, it may trigger the moth to flame phenomenon. I worry that this could be especially true with folks who are tired or have been drinking. In any event, I think the real issue is less about blinking or not, and more about how to be conspicuous, and lighting alone seems to fall short. Take a look here: You're not as visible on a bike at night as you think, new study shows | BikePortland.org