If "Privacy Badger" blocks cookies, then it's probably the old "The operation is insecure." That's what I see. A message says "Please select up to three locations," but there is no list of locations.

People, please use a try/catch when feature testing for localStorage. If cookies are blocked for the domain, trying to access storage will throw a security exception. This exception will almost definitely hose whatever behavior you were trying to add. I see this on probably 60% of Show HN projects, but sometimes even on large sites.

Your core competency is testing web sites, right? I'd suggest making one of those 200 locations block cookies. You'll find 10x as many defects.

(edit And I'm assuming that localStorage is almost never really necessary for these sites, but that some bit of the framework tests for it without the developer even realizing it. So yes, I consider that a defect.)