If I hooked up a zen vision into the video and audio RCA inputs on the back of the D3 so that I could view the Creative interface on the D3 while navigating with a remote, would the bypass be necessary while driving?

since it is a video source i am going to say yes...but that is just a guess

since it is a video source i am going to say yes...but that is just a guess

You would be correct. Any video source is locked out while driving unless you do the bypass.

yup all video is blocked while the bypass is not in effect. Save yourself the trouble and do the bypass.