There’s an old saying, “Give an inch and they’ll take a mile.” Sometimes that’s said about something rather “innocent” (comparatively speaking) that a child does, but sometimes it has reference to a practice that has moved well beyond “innocent.” The popularity of 
self-service fountain drinks in restaurants and gas stations is going to cost certain “consumers” more than they figured (eternally!). One fast-food restaurant owner found out that the employees down at the bank had kept a cup from his restaurant and were taking turns each day bringing it in and filling up on “free refills.” He finally put up a sign, “No refills after leaving the restaurant.” One restaurant that gives out small cups for free water has posted a sign, “Water doesn’t bubble.”
Too many people want to get more than they actually paid for (or get something when they didn’t actually for anything at all). Either action is, basically, stealing. How far have we drifted that we think “free refills” means “forever refills”? Actually, we know it doesn’t! The devil is using a simple thing like a fountain drink to test one’s devotion to honesty. Simple but effective!