Good points...I own a lone wolf climber and am very pleased with it. It comes with two straps that keep the bottom platform from falling out...has it ever happened to me? No...but what has happened is it may drop further than you can reach on the descent...and the only thing stopping it from completely dropping are those two straps...they also serve to keep the upper platform (seat) from dislodging as well if you bump it. As others here said, when used properly they are very safe...just take your time and ensure you are wearing your harness and have your sling around the tree as you climb and descend...in my experience that's when there is the potential for problems/accidents...once your at your desired height and secure there is little that can go wrong, unless you fall asleep! I love my climber, for me it provides the perfect combination of flexibility and portability. Oh one other thing that msbadger alluded to...when you start at the base you want your cables snug enough that they pitch the platforms upward on a slight angle. This will ensure your platform is level and not on a downward angle once you get to the desired height where the diameter of the tree decreases. Positioning can be tricky and is a matter of preference, comfort level, and surrounding cover. I personally put my stand on the opposite side of the tree from where I believe the deer will approach. i like to keep the tree between me and the deer. I also like to set up in trees that have other trees with foliage close behind me to camouflage me, especially since i most cases the tree you select won't have any at your desired height. For the first and last couple hours of hunting light, when the deer are most active I stand just so I'm ready to go..the rest of the time and between I alternate standing and sitting. You'll most definitely want to practice and play with your setup before you actually hunt so you know where you want to hang your bow, accessories, quiver, pack etc. the wrong time to figure this out is the morning of an actual hunt, fumbling and making a racket as a buck blows by your stand...had that happen to me already
Best of luck!