To be honest, no, I don't use my eyelids to block anything, and I don't think that's a reasonable thing for a person to do. I don't use any muscles to block billboards; I just look at whatever I was originally planning to look at (usually the road ahead of me), and don't expend much mental or muscular effort to pay attention to OR ignore billboards. The closest I might come is to turn away from ads playing at the gas pump. But that could easily be classified as choosing not to look vs. blocking.