I think we should not let the perfect become the enemy of the good with
regard to measuring impact.
If we see a large cohort of first-time Buenos Aires attendees show up at
later meetings (Berlin being the first chance for them to show), we have
a strong signal that they thought it was worth it, and likely that
having the meeting in BA helped the community by helping recruit them.
Personally, I don't care whether they show up in Berlin, I care
whether they show up on mailing lists writing drafts and editing and
reviewing them.
I'd be rather surprised if a lot of new participants from Argentina
showed up in Berlin, because if you live in, say, Mendoza, it's orders
of magnitude more expensive to get to Berlin than to B.A.
R's,
John