Clicking on the first entry for G Fecht, I obtained the following screen: 
It's difficult to see in the image in the post (click on it for a larger shot), but Ancestry.com's indicating this is from Iroquois County when the image clearly states Hancock. I suspected the error based upon the name I searched for and the name of the township, but would the "unsuspecting" genealogist--I'm not certain.
I love having these things indexed, don't get me wrong. It would be nice however, if the correct county were tied to the database entry.
Of course, this does give me a nice citation issue to discuss for the newsletter, but that really is not the point.
Update: the 1916 Hancock County, Illinois atlas is listed Jersey County......