It's something that we all have to deal with. At the end of the day, we have the night chests that will re-fill. If you are able to survive until then, you still have a shot at coming. If you know a trail of chests outside of the cornucopia, than you should be fine. If you can only depend on the cornucopia for your items, I would try looking for more chests outside of the area. As an answer to your question, it's not necessarily a hack every time. There may have been only one item in the chest and they clicked on it. I don't think anyone would really go out of their way, just to chest hack...