I roll a few dice in advance for these. Players are welcomed to check them after the fact. I take the rolls one after the other. It takes about a minute to roll about a dozen (never needed that much...) and I check them when they are used up. It makes for a faster pace and since they do not hear dice rolling the surprise is usually guenine.Most of my rolls are done in the open, but for those few rolls where the element of surprise or uncertainty is necessary, such as rolling to see if someone believe a lie or notice a hidden character, I prefer to hide the result of Lady Fortune.