Earlier quoted context omitted.
That's the competitive reality of driving in congested, urban areas. Drivers who cut in can save a lot of time over the course of a commute. They disrupt traffic flows and delay everyone else. So efficient traffic flows have to be defended. > Surely all drivers have to change lanes at some point to get where they're going; Yes, and some drivers like, for instance, to pass around 25 other cars who are making the same…
Although zipper merges are supposedly more efficient :-) http://arstechnica.com/cars/2014/07/the-beauty-of-zipper-mer...
If you're not one of these drivers, it benefits your trip time if you prevent their actions by not creating easy opportunities for them to slip in.
If you are one of these drivers, it benefits your trip time if you successfully carry out the zig-zagging. To that end, it behooves you not to announce your intended moves. If you do, you reduce your opportunities, because you're relying on those who enable this behavior by letting zig-zagging drivers in. In other words, not-blinking is a rational game strategy.