I use a thing called a sling!
Even when using a climber, I'll pull the sling over my head so my firearm is across my back,
safely unloaded of course. No different then me climbing manually or in a lock on with a daypack on.
I know where my gun is all the time (on my back, unloaded) so it's not going anywhere. I personally don't want any of my high dollar guns or optics banging on limbs, metal tree steps, or anything else on it's way up or down. Just my preference I guess. I suppose some may think that's not the safest thing in the world, but that's what a saftey belt is for.
I'd rather not damage my gun or optics and most of you know I'm a stickler about accuracy. That bullet will hit where my crosshairs are every time when my gun never leaves my body. Now I have no problem using a rope for a bow, in fact I know of no other way to do it without being totatlly unsafe.
I think your product is an awesome idea and would use it once I got into my stand just for the fact that it would save a 20' drop if I accidently let my rifle go. I don't use ladder stands and RARELY use lock-ons, in fact I only own 1! Most of my climbing is done manually with my Loggy Bayou and my gun is always on my back going up and down. I'll be buying a few of your products for family and friends b/c it's a great idea and a good stocking stuffer for this Christmas!