Safety harnesses are your friend!
Once I got my climbing stand to the 20 foot mark and turned around to sit down. When I did the top half of the stand skidded down the tree (wasn't seated good in the slick bark) I almost fell and may have had I not been harnessed. The top half of the stand got stopped by the bottom half and I got stopped by the harness. Took a bit of creative gymnastics to get everything back where it was supposed to be.
(almost took a change of underwear for me to complete the hunt too)