Yes, there is that conventional wisdom saying it
doesn't make sense to call yourself Berliner if you
live in Berlin, because a zillion other people do,
too, so it doesn't distinguish you.
HOWEVER the surname SCHLESINGER would seem to derive
from Schlesien, which is Silesia, a region now inPoland >from which I have much ancestry. And guess
what? I have SCHLESINGERS >from Wroclaw, the capital of
Silesia, in my family tree, and it was so common a
surname there, that it's impeded my tracing that
branch of the family almost completely.
I have to say, the way our ancestors chose surnames
are a complete mystery to me, in spite of the ways in
which researchers have tried to make sense of the
process long, long after the fact.