Astounding - this small feature dramatically improves my results with google.
This is the first time I've even heard of this mode. As with the original article, I think this speaks to the massive power of the "default". Once upon a time Google's "default" was excellent for my use case, but it's slowly degraded over the years, and rather than dig through all of its options trying to make Google useful again, I just whined about it and started looking at competing services.
Changes in default behavior should be embarked upon with extreme caution. This is especially true when considering the way google does this (with many incremental changes that are totally invisible individually). I feel like if they more prominently highlighted 1) what they were changing and 2) how to work around it they could avoid much backlash from "power" users.
Firefox, in contrast, makes it very clear what they're doing when they change the default search engine, and it's pretty easy to switch back to google. But clearly for a large number of users, that "default" will be good enough.