This past Friday I discovered this device that our forestry crews use. Cheap insurance!  http://www.millerfallprotection.com/fall-protection-products/accessories/relief-step-safety-device

My favorite advice is to stay out of them!!!!  :D    :D    :D

I carry a small screw in tree step with me so that I can screw it into the tree to take the weight off the legs and help get back up into the stand if necessary.