I think the prior for aliens having visited Earth should be lower, since it a priori it seems unlikely to me that aliens would interact with Earth but not to an extent which makes it clear to us that they have. My intuition is that its probably rare to get to other planets with sapient life before building a superintelligence (which would almost certainly be obvious to us if it did arrive) and even if you do manage to go to other planets with sapient life, I don’t think aliens would not try to contract us if they’re anything like humans.
I think the prior for aliens having visited Earth should be lower, since it a priori it seems unlikely to me that aliens would interact with Earth but not to an extent which makes it clear to us that they have. My intuition is that its probably rare to get to other planets with sapient life before building a superintelligence (which would almost certainly be obvious to us if it did arrive) and even if you do manage to go to other planets with sapient life, I don’t think aliens would not try to contract us if they’re anything like humans.