I guess I've just been very lucky. I would be lying if I said I didn't worry about it though but as I said I usually just lift it up to where I can support it from the bottom and carry it that way if I have to. Fortunately I have hardwood floors in my house and I just scoot it when I can.
That's prpbbaly fine I would still probably use it to gently drag a full carboy into place... slowly.