Just to add some perspective here, the European summer tourist season is over and I don’t think it’s clear at all that the EU would not act first in restricting travel from the US if clusters are discovered there, so whether the US should impose a travel ban on Europe could equally become a moot point. After all, the current ‘US travel ban’ is really nothing of the sort and US citizens will continue flying into the US over the near term from Southern Africa requiring only a test three days before departure if vaccinated, giving ample time to subsequently get exposed to the Omicron variant then spread it around the US.