If not done universally, allow me to activate this feature in my preferences.
I tried DDG a few times but always switched back to Google eventually (typing <BACK> and then <SPACE> "!g" <ENTER> is tiring, especially on mobile). I think this option would make me switch to DDG indefinitely.
javascript:(function(){ var s = document.location.search.split("&")[0].substr(1); document.location = "https://encrypted.google.com/search?hl=en&"+s; })();
To be clear: while this button directs people away from DDG to Google, it actually allows people to use DDG as their first (main) search engine, and lets them switch to Google if necessary without much inconvenience. The better the DDG search results, the less views they lose to Google.
The workflow is exactly the same: Search for stuff in DDG, and if you suspect that Google might have returned a better result, prepend "!g " to your query (which might be even faster than clicking on the bookmarklet, depending on how fast you type).
BTW, you can also search through StartPage instead by using !sp, or Bing, etc so there's nice flexibility there.