A friend of mine recently bought 4 quarts of 20w50 Mobile-1 Synthetic from Wally-Mart. He started to open the first quart and noticed the little "security" thing wasn't appearing to be attached. never the less, he began to pour the oil into the funnel, notcing it was WATER. Someone used the oil, and returned the containers, filled with water. Nobody looked close enough, and they ended back on the shelf, as returned stock.