Have instructions on this but cannot find them.... seems there was something extra you do at the ends to add material which stops the pull, but I just don't remember because I've never done this method.
Back when I was checking into this Rag Rug business I discovered RR-crocheting and that was the method I used for my bathroom oval rag rug. All shapes can be made with crocheting and I didn't have to build the weaving frame. I sewed the strips together instead of knotting, and folded them so the raw edges didn't show for a smoother look.
Click here for larger image of my rag rug
http://www.currentwave.com/RagRug-lg800.jpg This winter, I plan on making a braided rug for the denser look, but it will be a lot more work than this crochet one.
I'll post if I ever find those directions.....
Good luck!