I'd have a few concerns, though. Call me a skeptic. I don't want to be "Martina-Downer" (SNL) but here it goes:
What happens if your carboy is not the exact size? It looks as though you need to have a 5 gallon carboy at least. I'd be frightened that the carboy could possibly slip through that thing when full. In my opinion, the bottom needs to be supported. The sides aren't just enough for me.
The nice thing about it, though, is that you can adjust the place where you tighten it. If it would have a bottom support system, I'd be sold.
Hey, you patent people: create one of those things with a plastic (or fabric, like the brew-hauler thingie) at the bottom, and we've got a winner, I think! Just wait, I'm giving my idea which is worth millions away like it were water in a flooded area.