Just dropping my personal choice: I will not travel by flight.
In or near Berlin is my personal requirement for attending any con.
If it were only up to me, I would permit unvaccinated attendance, but this
choice includes all of society. I am not ready to take the responsibility to
partake in a gathering that allows likely spread of COVID. Consider the case
that it results in infection and possibly long covid and/or death of an
attendee or her family / friends.
My choice to categorically not travel by flight goes along the same lines,
related to greenhouse gas emissions. A single intercontinental flight
*quadruples* my personal annual emissions. It's way out of proportion.
~N