So I got the Ring Wrapper (purple of course) and finally got to go ride in the mud. I had NO questions about it falling off - my ring was very secure on my finger - and it mostly shielded the mud too. I don't like to ride with gloves in the summer time because they are hot, so I'm really glad I found this product!
I ran across this thread and figured there must be SOME solution out there... well I found one and wanted to share it with y'all... I found it on a running forum but I bought a purple one to match my helmet. www.ringwrapper.com
I'll let you know how it works out when I get it!