Pretty sure all of you know about this, but I personally want to hear what you guys think about this and for those of you who somehow missed this. Ignoring the "integrity" of the game, I would call the runner out on a borderline call in an instance such as this if I was the ump, for my own reputation. If the runner is called out but is really safe, it'll just be perceived as a good break for the pitcher and a natural human error. If the runner is called safe but is really out, then the ump would be considered a goat for a long time to come.