Weve known for like Google does and can deal with the same URL however with various cases in a different way. So domain.com/Apple vs domain.com/apple can be seen by Google as various URLs. Google seems to be stricter about this guideline when it comes to the robots.txt file.With domain.com/Apple vs domain.com/apple, Google can tell if the pages are similar and will canonicalize the URL to one of them, so both will not show up in search and Google might consolidate the signals as well.But maybe if you have a robots.txt instruction for domain.com/apple however not for domain.com/Apple, Google may not utilize Robots directive?John Mueller from Google published video on URL case level of sensitivity and at the 1:08 mark stated “another location where the precise URL plays a role is robots.txt. In the robots.txt file you can signal which parts of a site should not be crawled. The robots.txt file also utilizes exact URLs. If you have entries there which refer to one variation of a URL, they would not use to other versions of that URL.” John did include that it is “unusual that we see this cause issues though.”So keep this in mind not simply for total how Google may canonicalize your URLs but also for robots.txt handling.Forum discussion at WebmasterWorld and Twitter.