Ok, I have a defective '09 Fit, mine doesn't shake at idle!

 

I notice mine yesterday for the first time.

 

Mine only does it when I turn the music up. I can't hear it, but the damn wiper bounces off the windshield.

 

I can see it vibrate like crazy, too. The only workaround I found was to put the gear in neutral (mine's AT) while waiting for the light to change.

 

Removed my little wiper back around the end of May, it honestly does not do all that much.
Plus if you use Rain-X or Aquapel (rain-x on steroids) you hardly use your wipers anyway as the rain beads up and flies off. It also looks a lot cleaner and uncluttered. qbmurderer13 and maybe some others have removed it as well.