Well,
@buckeyebri specifically mentioned lane reduction, yes? I read his complaint as being in regards to the situation I presented, not the one you presented. And the article specifically mentions that it doesn't work as efficiently when traffic is moving -- if everyone is cruising along at 30 and one a-hole pulls your trick, yes that will screw things up. But if both lanes are full at 10 MPH, the zipper works better.
The problem is that people don't use both lanes and instead will stop in their lane to merge 1/4 mile before the merge point, which just creates more congestion and backs the traffic up even further. And then the guy who understands that using all of the available road and drives all the way to the merge point becomes an a-hole for going all the way up there. But......if everyone would have been going all the way to the merge point originally, it wouldn't have been as screwed up!