Frustrating it took this long for something to be done about this, but glad its now got something being done.
It seems pretty stupid. Instead of expanding the SEO policy bureaucracy to address a situation where a spammer hijacks the back button, the browser should have been designed in the first place to never allow that hijacking to happen. Second best approach is modify it now. While they're at it, they should also make it impossible to hijack the mode one.... oh yes, Google itself does that.