I've never hung a "hang-on" before. I have one but just never got around to hanging it. I was planning on using my climber to get to the deisred height and then pull the stand up with a rope and then secure it to the tree. Seems like that would be fairly safe.
ducsauce installing treesteps and climbing sticks are very safe. Hanging a stand is very safe. Just use a safety line and harness. Most of all use a safey line attached to your harness while installing a hangon stand, leaving both hands free and your weight will be balanced. Again......installing and using hangons are very safe when the technique used is correct.