I had seen this described on a video or two on YouTube, of course, I promptly forgot which ones so here I am inquiring of you all:

What is the technique or tool that is used for the end of tubing line (I'm thinking specifically for 3/16 tubing in this case, with the end being the line anchored around the first / top tree) so that most of the exposed tubing around the tree is "inert?"

I saw more than one person describe how they "block off" the tubing for most of the wrap around the tree that anchors the line, suggesting that is the area "more often than not" that is chewed by squirrels or deer. Is it some kind of end-of-line hook?

The only end-of-line hooks I've found locally are essentially an elbow and still leave the entire length of tubing "live" to the natural vacuum of the rest of the line.