I was driving over to LaCrosse today and hit a spot where the left lane was closed for some work on a bridge. There was a pretty decent backup, but traffic was moving. About 3/4 mile from the lane closure, everyone merges right and only a few cars are staying in the left lane, including myself. About a half-mile from the lane closure, some guy in the right lane pulls halfway into the left lane, actively blocking people from using the zipper method (I guess we all had to zipper a bit early). I really want to see a widespread PSA campaign promoting the use of proper zippering.