The only drawback is that there are four straps on the top/bottom edge, and flimsy elastic loops on the sides that attach to the straps.
I was thinking I could cut off the elastic loops, then reinforce the edges and add grommets all around, so there are more tie-down points. Then a long piece of cord to tie them on tight. A little work, but might be worth it.
At first I was going to take a 4' x 6' Canvas tarp, and wrap the seat and tie it in back. Would have been heavy duty, and easy to remove and wash. Problem is Army green would clash with my Fire Engine Red doors!