Not a new idea, but new for us. I'm always putting my partner's glass in the dishwasher before he's done with it. I can't help it in the same way I always kick over glasses wherever they are. It's simply part of my makeup. Consequently, he has six glasses and I never know which one is up for grabs or in circulation. I slip these on the glasses in play and they remain safe from my clean up frenzy. It's a good way to distinguish drinks at a party too. I've seen little wine glass jewels, but have never thought about the coffee sleeve for regular drinking glasses.