bingopodcast on "Turf King keys?"
Wednesday 22 November 2017 at 21:29
Wow! My game does not have that at all. Very interesting. In practice, it's so hard to earn the feature award, I can see why you wouldn't want that to be removed with regular gameplay. 
Source: http://pinside.com/pinball/forum/topic/turf-king-keys#post-4086787