bah.....nothing wrong with double-stacking, as long as you PUT PLYWOOD BETWEEN THE LAYERS! You can see in the OP's post that they didn't do this......you can imagine the lift driver trying to take the top layer off...his forks WILL rip the cover at least, and the bags, at the worst, when he/she tries to get the top skid of pellets off. Also, its less stable without the plywood in between. Putting plywood on top is dangerous. Not only will it fall when you take a skid off, possibly hurting someone, but Ive seen the wind blow sheets off the top, which is REALLY dangerous. Likely the pallets on the top keep the birds from puncturing the cover, and far less likely the get blown off.