Dunno, but unless you also put a UV protected cover over the glass, you are only reducing the surface of what the sunlight can hit the beer on. Still going to shine down on the top of the beer.
I sat out on my back deck in direct sunlight last weekend while brewing up the next batch, and with the sun and the heat, the beers we were drinking (in normal glasses) would loose their chill fairly quickly, but even over a period of 15-30 mins, they would warm up, but never went skunky. Anyone leaving their beer un drunk for longer than that needs to hurry up. Don't see this as an issue here, maybe in warmer climates possibly, but still.
I would think that the glass would actually hurt your beer sales, as the beer will last longer, therefore people buy less, kinda shooting themselves in the foot me thinks.