"2. It would snag on branches as you walk through thick brush."
Keith,
No they don't. When sheathed all that is required is to pull the loose wrist thong (from the rear) through the bottom portion of the sheath opening, between your belt and the sheath's belt loop. You can go one step more and pull it through to the front. You'll never lose a Randall knife this way. You can give the wrist thong a quick tug and it's free for you to unsheath the knife.
Best, Capt. Chris
Yeah, well, I'm just telling my experience with them in the past. I've tried the tuck method you described and it still snagged eventually, although it was much more secure that way.
I've had my nylon boot laces come untied several times after double-knotting them and tucking the loose ends into my boots. When you have briars pulling and ripping at your clothes, there is not much you can do.