Given the nature of 3D expansion and the size of galaxy vs the age of the universe 0.1c vs 1C isn't really that big of a difference. However I do wonder why th

Given the nature of 3D expansion and the size of galaxy vs the age of the universe 0.1c vs 1C isn't really that big of a difference. However I do wonder why the fermi folks get all bent out of shape about not seeing other civilizations. How far do you think you could see a fusion or antimatter ship accelerating or deaccelerating from 0.1c? Unless they are zipping around our solar system (Expanse style) doesn't seem likely the we'd notice them. If the aliens were curious about us and had detected our expanding RF emissions they might well be close by listening. Seems far from clear that civilizations would bother messing with stars (that would be detectable from a decent distance) instead of just propagating to other solar systems. People are already talking about sending probes to our nearest star via laser propulsion.