It could be a good sign. If she starts dragging her butt on the floor, check her rectum to see if maybe the elastic is coming out. VERY GENTLY tug on it to see if it'll come out. If it stops, DO NOT PULL ANYMORE...get her to the vet.

My Munchkin loves to chew on dental floss, ribbon, thread, anything she can get into. So I have to watch her because she's cost me a lot of money in vet bills twice for chewing on dental floss and thread.