I disagree. If you assume that drivers can't see you, you will not be defensive enough! When I ride, I assume that the drivers on the road are going to do whatever they can to run me down!
I'm also pretty nervous for another reason. While driving my CAR, I've been rear-ended at stop lights 3 times in the last 8 months! Now, I'm a big guy (6'4", 300#), but if they can't see my car, how the hell are they going to see me on my Duck?
Mark
I took this concept a step farther. I mentally approach every intersection or driving in close quarters with the thought that people are TRYING to hit me. That doesn't mean I ride in constant fear, it just means that I'm not going to give others even the slightest benefit of doubt. It has allowed me to, as Spock would say, Live Long and Prosper.