This question was inspired by a 2014 case in South Carolina, where a man named Christopher Lewis was given a $525 ticket (later reduced to a warning) for refilling a drink at a VA Medical Center.
In Mr. Lewis' case, supposedly there were signs prominently displayed saying "No Free Refills." But the problem is that, in the vast majority of restaurants with self-serve drink fountains, there is no signage whatsoever about refills.
I know that normally you can't just take whatever you want for free, but I also feel like enough restaurants are fine with free refills that this could be considered standard practice in the industry.
Is there a default position on drink refills? Could you get in trouble for refilling if there is no signage?