I don't understand the relevance of #1, as we have no time machine. Regarding #2, I think no one seriously thinks the vaccine could fail to prevent spread (it

I don't understand the relevance of #1, as we have no time machine. Regarding #2, I think no one seriously thinks the vaccine could fail to prevent spread (it surely is not 100% sterilizing, but everyone acts under the assumption it will vastly reduce spread). "There is no evidence for X" can be said for the vast majority of values of X, since most X are impossible and/or too time consuming to study. This includes, for example, X = "the best way to use the vaccine is to give a first round of second doses before a second round of first doses". But we often have to make decisions in the face of imperfect data. #3 is ridiculous because the logic appears to be, "the best rollout plan is the one that's easiest to enforce". By this logic, we should line up by height, like we did in elementary school when heading to the toilet.