I started with an old Baker climbing stand, and the "safety strap" went around your waist. I had to bear hug the trees to climb them (like Natty said he did). Looking back, if the stand would have slipped - or I lost my balance - I would have been left hanging by my waist, probably with a ruptured spleen from the shock of the belt biting into my innards, and bleeding out or suffocating while hanging there.
I've seen old wooden pallets nailed into trees, 2x4's nailed for steps, all kinds of rickety wooden rigs nailed into trees that I wouldn't have climbed into if they were NEW!!! The craziest thing I ever saw was a pick-up truck cap fastened into a tree as a shelter from the weather. It was about 18 ft. off the ground. I would have loved to have seen the installation of that thing!!!