Citizens Bank (Water) Park

So the World Series is the last series in Major League Baseball's season.  Presumably, if they postponed a game, they could just shift a game into the off-day(s) scheduled into the series.  If they had to do it twice, they could simply shift Game 7 (if necessary) to October 31.  

Why, then, was Game 3 delayed for over an hour and a half, leading it to end at quarter to 2 in the morning, and why in Willard Scott's name are they playing right now?