Tom, we made videos in hunter safety classes. This video was viewed and remade by the treestand manufacturers group and adapted by the International Bowhunter educators. Most of the treestand training you see in the NBEF and hunters safety is from our training, nearly word for word.
There is a really good reason you hardly see any straps issued with treestands any more. I have come out of treestands many times in the classes (that's why we made the video). Been there, done it.
We teach to adjust the tether strap so that there is no slack at all when you are sitting. I rolled out of that stand, best case scenario, and half the time I couldn't "save myself", needing help. I also couldn't breathe, nearly immediately.
My partner did the same in a Seat of the Pants, which was about the only full harness available at the time. He hung there, continued his presentation, and spun around and climbed back aboard the stand.
If you fall, and the strap is adjusted rght thats one thing. Actually, there is a good chance you won't come out of the stand. If the stand breaks, you are likely to break ribs and hang upside down.
I am not gonna claim to be an expert at this, but I "been there. . done that", on film and off. I will not wear a waist strap any more, period.
ChuckC