It was down to health and safety reasons. You see, people love Heinz beans so much that they bought tins and tins of them, however they did not have enough room in their cupboards to put them side by side. Instead they started stacking them on top of each other until the stacks became unsteady and toppled over causing slight to severe injury and sometimes even death by crushing. Heinz realised they had to do something, so they changed the design of their tins so they could not be stacked on top of each other. Since they did this, reported injury and death by Heinz can has dropped dramatically. So there you are!!