While it does smack a little of the arrogance of a big player, they are using the fragment part for more-or-less what it used to be used for (navigating to a specific location on a page), and if you use something in a way it isn't intended (using a navigation aid for state management) perhaps you should expect certain things to break at some point when combined with other hacks of the same feature.

It is important to note that this won't break your site/app in the normal use case. People using your work will continue to do so uninhibited unless/until they wish to use this new feature in Chrome.